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54 results on '"European Theoretical Spectroscopy Facility (ETSF)"'

1. Connector theory for reusing model results to determine materials properties

Author: Marco Vanzini, Ayoub Aouina, Martin Panholzer, Matteo Gatti, Lucia Reining, LSI - Spectroscopie théorique (ST), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), European Theoretical Spectroscopy Facility (ETSF), Johannes Kepler Universität Linz - Johannes Kepler University Linz [Autriche] (JKU), Uni Software Plus GmbH, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), the Austrian science Fund FWF under Project No. J 3855-N27, and European Project: 320971,EC:FP7:ERC,ERC-2012-ADG_20120216,SEED(2013)
Subjects: electron-gas, kinetic-energy, Computer Science Applications, gradient approximation, Mechanics of Materials, Modeling and Simulation, linear-response, systems, General Materials Science, exchange-energy, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], density-functional theory, accurate, nonlocal approximation, expressions
Abstract: The success of Density Functional Theory (DFT) is partly due to that of simple approximations, such as the Local Density Approximation (LDA), which uses results of a model, the homogeneous electron gas, to simulate exchange-correlation effects in real materials. We turn this intuitive approximation into a general and in principle exact theory by introducing the concept of a connector: a prescription how to use results of a model system in order to simulate a given quantity in a real system. In this framework, the LDA can be understood as one particular approximation for a connector that is designed to link the exchange-correlation potentials in the real material to that of the model. Formulating the in principle exact connector equations allows us to go beyond the LDA in a systematic way. Moreover, connector theory is not bound to DFT, and it suggests approximations also for other functionals and other observables. We explain why this very general approach is indeed a convenient starting point for approximations. We illustrate our purposes with simple but pertinent examples.
Published: 2022
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2. Electronic properties of the five principal stackings of boron nitride moiré bilayers

Author: Latil, Sylvain, Amara, Hakim, Sponza, Lorenzo, Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Laboratoire Matériaux et Phénomènes Quantiques (MPQ (UMR_7162)), Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Saclay, ONERA, CNRS, Laboratoire d'étude des microstructures (LEM), ONERA-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), HEP, INSPIRE, Service de physique de l'état condensé (SPEC - UMR3680), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and European Theoretical Spectroscopy Facility (ETSF)
Subjects: [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [INFO]Computer Science [cs], [INFO] Computer Science [cs], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], [PHYS.COND] Physics [physics]/Condensed Matter [cond-mat], [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph]
Abstract: 12 pages (5.5 main text); 14 figures (5 in main); 4 tables (3 in main). Supplemental materials concatenated to main text; All theoretical calculations on boron nitride moir\'e bilayers report the properties of, at most, two possible stackings which preserve the monolayer hexagonal symmetry (i.e. the invariance upon rotations of 120°). In this work, we demonstrate that, for a given moir\'e periodicity, the same symmetry is respected by five different stackings and not only two as always discussed in literature. We introduce some definitions and an appropriate nomenclature to identify unambiguously the twist angle and the stacking sequence of any BN bilayer with order-3 rotation symmetry. The nomenclature we introduce here and the method to calssify stacking sequences and the angles is completely general and can be applied to homobilayers of any hexagonal 2D materials. Moreover, we produce density functional theory predictions of the electronic structure of each of the five stacking sequences at six different twist angles and discuss the evolution of the gapwidth and band structure and as a function of these parameters. We show that the gap is indirect at any angle and in any stacking and we identify features that are conserved at any angle within the same stacking sequence.
Published: 2022

3. Comparison of long-range corrected kernels and range-separated hybrids for excitons in solids

Author: Rita Maji, Elena Degoli, Monica Calatayud, Valérie Véniard, Eleonora Luppi, Véniard, Valérie, Università degli Studi di Modena e Reggio Emilia = University of Modena and Reggio Emilia (UNIMORE), Laboratoire de chimie théorique (LCT), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), and European Theoretical Spectroscopy Facility
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, Time dependent density functional theory kernels. LiF Si, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, [PHYS] Physics [physics]
Abstract: The most accurate theoretical method to describe excitons is the solution of the Bethe-Salpeter equation in the GW approximation (GW-BSE). However, because of its computation cost, time-dependent density functional theory (TDDFT) is becoming the alternative approach to GW-BSE to describe excitons in solids. Nowadays, the most efficient strategy to describe optical spectra of solids in TDDFT is to use long-range corrected exchange-correlation kernels on top of GW or scissor-corrected energies. In recent years, a different strategy based on range-separated hybrid functionals started to be developed in the framework of time-dependent generalised Kohn-Sham density functional theory (TDGKSDFT). Here, we compare the performance of long-range corrected kernels with range-separated hybrid functionals for the description of excitons in solids. This comparison has the purpose to weight the pros and cons of using range-separated hybrid functionals, giving new perspectives for theoretical developments of these functionals. We illustrate the comparison for the case of Si and LiF, representative of solid state excitons., 25 pages, 11 figures
Published: 2022

4. Robustness of the chiral-icosahedral golden shell I-Au 60 in multi-shell structures

Author: H.-Ch. Weissker, Sean M. Mullins, Robert L. Whetten, Xóchitl López-Lozano, UTSA Department of Physics and Astronomy [San Antonio], The University of Texas at San Antonio (UTSA), Northern Arizona University [Flagstaff], Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), European Theoretical Spectroscopy Facility (ETSF), ANR-14-CE08-0009,FIT SPRINGS,Des Transitions Individuelles aux Résonances Plasmon de Surface dans les Agrégats d'Or et d'Argent(2014), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Fullerene, Nanostructure, Materials science, 010405 organic chemistry, Icosahedral symmetry, Shell (structure), General Physics and Astronomy, Rigidity (psychology), 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Symmetry (physics), 0104 chemical sciences, Electronegativity, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Chemical physics, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: International audience; Motivated by the recent theoretical discovery [S.-M. Mullins et al., Nat. Commun. 9, 3352 (2018)] of a surprisingly contracted 60-atom hollow shell of chiral-icosahedral symmetry (I-Au60) of remarkable rigidity and electronegativity, we have explored, via first-principles density functional theory calculations, its physico-chemical interactions with internal and external shells, enabling conclusions regarding its robustness and identifying composite forms in which an identifiable I-Au60 structure may be realized as a product of natural or laboratory processes. The dimensions and rigidity of I-Au60 suggest a templating approach; e.g., an Ih-C60 fullerene fits nicely within its interior, as a nested cage. In this work, we have focused on its susceptibility, i.e., the extent to which the unique structural and electronic properties of I-Au60 are modified by incorporation into selected multi-shell structures. Our results confirm that the I-Au60 shell is robustly maintained and protected in various bilayer structures: Ih-C60@I-Au60, Ih-Au32@I-Au2+60, Au60(MgCp)12, and their silver analogs. A detailed analysis of the structural and electronic properties of the selected I-Au60 shell-based nanostructures is presented. We found that the I-Au60 shell structure is quite well retained in several robust forms. In all cases, the I-symmetry is preserved, and the I-Au60 shell is slightly deformed only in the case of the Ih-C60@I-Au60 system. This analysis serves to stimulate and provide guidance toward the identification and isolation of various I-Au60 shell-based nanostructures, with much potential for future applications. We conclude with a critical comparative discussion of these systems and of the implications for continuing theoretical and experimental investigations
Published: 2021
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5. Optical properties of Ag$_{29}$(BDT)$_{12}$(TPP)$_4$ in the VIS and UV and influence of ligand modeling based on real-time electron dynamics

Author: Rajarshi Sinha-Roy, Hans-Christian Weissker, Robert L. Whetten, Xóchitl López-Lozano, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), UTSA Department of Physics and Astronomy [San Antonio], The University of Texas at San Antonio (UTSA), Northern Arizona University [Flagstaff], ANR-11-IDEX-0001,Amidex,INITIATIVE D'EXCELLENCE AIX MARSEILLE UNIVERSITE(2011), ANR-14-CE08-0009,FIT SPRINGS,Des Transitions Individuelles aux Résonances Plasmon de Surface dans les Agrégats d'Or et d'Argent(2014), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
Subjects: Materials science, 010304 chemical physics, Ligand, Time evolution, Aromaticity, Electron dynamics, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, chemistry.chemical_compound, chemistry, 0103 physical sciences, Cluster (physics), Molecule, Physical and Theoretical Chemistry, Absorption (chemistry), Benzene
Abstract: We study the optical properties of the $$\hbox {Ag}_{29}$$ (BDT) $$_{12}$$ (TPP) $$_4$$ cluster, the geometry of which is available from experimental structure determination, by means of Fourier-transformed induced densities from real-time (time evolution) calculations of time-dependent density-functional theory. In particular, we demonstrate the influence of the ligands on the optical spectra in the visible region and, even more, in the UV. A strong peak in the UV reminiscent of the spectrum of isolated benzene is found to be caused by the phenyl rings of the TPP ligand molecules. Nonetheless, their absence in the modeling also impacts the absorption in the visible region substantially. By contrast, the aromatic rings of the BDT ligands are more strongly coupled to the silver core and loose the character of independent oscillators; they contribute a much less peaked UV absorption. Our results underline the importance of properly accounting for the full ligands for precise and reliable modeling.
Published: 2021
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6. Halogen molecular modifications at high pressure: the case of iodine

Author: Miguel A. L. Marques, Jean-Paul Itié, Silvana Botti, Alain Polian, Emiliano Fonda, Tetsuo Irifune, Jingming Shi, Toru Shinmei, Pierre Lagarde, Alfonso San-Miguel, Anne-Marie Flank, Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), School of Physics and Electronic Engineering, Jiangsu Normal University (JSNU), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut für Festkörpertheorie und -optik (IFTO), Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], European Theoretical Spectroscopy Facility (ETSF), Martin-Luther-Universität Halle Wittenberg (MLU), Geodynamics Research Center [Ehime], Ehime University [Matsuyama], Earth-Life Science Institute [Tokyo] (ELSI), Tokyo Institute of Technology [Tokyo] (TITECH), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), and Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], 0303 health sciences, Materials science, Hydrogen, Absorption spectroscopy, fungi, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, 021001 nanoscience & nanotechnology, Iodine, Diatomic molecule, Dissociation (chemistry), 03 medical and health sciences, [SPI]Engineering Sciences [physics], chemistry, Chemical physics, Halogen, Chlorine, Molecule, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 0210 nano-technology, 030304 developmental biology
Abstract: International audience; Metallization and dissociation are key transformations in diatomic molecules at high densities particularly significant for modeling giant planets. Using X-ray absorption spectroscopy and atomistic modeling, we demonstrate that in halogens, the formation of a connected molecular structure takes place at pressures well below metallization. Here we show that the iodine diatomic molecule first elongates by ∼0.007 Å up to a critical pressure of Pc ∼ 7 GPa, developing bonds between molecules. Then its length continuously decreases with pressure up to 15–20 GPa. Universal trends in halogens are shown and allow us to predict for chlorine a pressure of 42 ± 8 GPa for molecular bond-length reversal. Our findings contribute to tackling the molecule invariability paradigm in diatomic molecular phases at high pressures and may be generalized to other abundant diatomic molecules in the universe, including hydrogen.
Published: 2021
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7. Investigating the magnetospheric accretion process in the young pre-transitional disk system DoAr 44 (V2062 Oph): A multiwavelength interferometric, spectropolarimetric, and photometric observing campaign

Author: Catherine Dougados, A. P. Sousa, C. Moutou, Jean-François Donati, Jean-Phillipe Berger, L. M. Rebull, Myriam Benisty, S. H. P. Alencar, K. Pouilly, Jerome Bouvier, Colin P. Folsom, Karine Perraut, Evelyne Alecian, Gilles Duvert, Amelia Bayo, Institut de Planétologie et d'Astrophysique de Grenoble (IPAG), Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France -Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Météo-France, Universidade de Lisboa = University of Lisbon (ULISBOA), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Spitzer Science Center, California Institute of Technology (CALTECH), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), European Theoretical Spectroscopy Facility (ETSF), new, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), the SPIRou consortium, Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA), Universidade de Lisboa (ULISBOA), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
Subjects: Rotation period, Astrophysics::High Energy Astrophysical Phenomena, FOS: Physical sciences, Magnetosphere, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, stars: pre-main sequence, 01 natural sciences, accretion, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), Astrophysics::Galaxy Astrophysics, Line (formation), Physics, stars: variables: T Tauri, Photosphere, stars: formation, 010308 nuclear & particles physics, Stellar rotation, accretion disks, Herbig Ae/Be, stars: magnetic field, Astronomy and Astrophysics, Light curve, Accretion (astrophysics), Stars, Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract: Young stars interact with their accretion disk through their strong magnetosphere. We investigate the magnetospheric accretion process in the young stellar system DoAr 44. We monitored the system over several rotational cycles, combining high-resolution optical and near-IR spectropolarimetry with long-baseline near-IR interferometry and multicolor photometry. DoAr 44 is a young 1.2 solar mass star, moderately accreting from its disk, and seen at a low inclination. We derive a rotational period of 2.96 d from the system's light curve. Several optical and near-IR line profiles probing the accretion funnel flows and the accretion shock are modulated at the stellar rotation period. The most variable line profile, HeI 1083 nm, exhibits modulated redshifted wings a signature of accretion funnel flows, as well as deep blueshifted absorptions indicative of transient outflows. The Zeeman-Doppler analysis suggests the star hosts a mainly dipolar magnetic field, inclined by about 20 deg. onto the spin axis, with an intensity reaching about 800 G at the photosphere, and up to 2 +/- 0.8 kG close to the accretion shock. The magnetic field appears strong enough to disrupt the inner disk close to the corotation radius, at a distance of about 4.6 stellar radii (0.043 au). This supports the upper limit of 5 stellar radii (0.047 au) we derived for the size of the magnetosphere from long baseline interferometry. DoAr 44 is a pre-transitional disk system, exhibiting a 25-30 au gap in its circumstellar disk, with the inner and outer disks being misaligned. On a scale of 0.1 au or less, our results indicate that the system steadily accretes from its inner disk through its tilted dipolar magnetosphere. We conclude that in spite of a highly structured outer disk, perhaps the signature of ongoing planetary formation, the magnetospheric accretion process proceeds unimpeded at the star-disk interaction level., Comment: 18 pages, 22 figures, Astronomy & Astrophysics, in press
Published: 2020
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8. How metallic are noble-metal clusters? Static screening and polarizability in quantum-sized silver and gold nanoparticles

Author: Hans-Christian Weissker, Rajarshi Sinha-Roy, P. García-González, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, and Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC)
Subjects: Materials science, Condensed matter physics, Shell (structure), Coinage metals, Nanoparticle, 02 engineering and technology, engineering.material, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Metal, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Polarizability, visual_art, engineering, visual_art.visual_art_medium, General Materials Science, Noble metal, Surface charge, 0210 nano-technology, Quantum, ComputingMilieux_MISCELLANEOUS
Abstract: Metallicity of nanoparticles can be defined in different ways. One possibility is to look at the degree to which external fields are screened inside the object. This screening would be complete in a classical perfect metal where surface charges arrange on the classical -i.e., abrupt - surface such that no internal fields exist. However, it is obvious that this situation is modified for very small clusters: the surface charges are "smeared out" at the surface, and the screening might be less complete. In the present work we ask the question as to how close small noble-metal clusters are to a classical metal. We show that, indeed, the screening is almost complete (≈96%) already for as little as one atomic layer of the coinage metals, silver and gold alike. At the same time, we show that quantum effects, viz., electronic shell closings and the Friedel-like oscillations of the density, play a role, meaning that the clusters cannot be described solely using the concept of screening in a classical metal.
Published: 2020
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9. Lattice vibrations and electronic properties of GaSe nanosheets from first principles

Author: Jamal Barvestani, Ali Soltani Vala, Elena Cannuccia, Friedhelm Bechstedt, Mousa Bejani, Olivia Pulci, NAST, CNR-INFM, European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Physique des interactions ioniques et moléculaires (PIIM), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Physics and Astronomy (miscellaneous), Band gap, Phonon, FOS: Physical sciences, Infrared spectroscopy, Lattice vibration, 02 engineering and technology, 01 natural sciences, Stability (probability), symbols.namesake, 0103 physical sciences, General Materials Science, Perturbation theory, 010306 general physics, Condensed Matter - Materials Science, Settore FIS/03, Condensed matter physics, business.industry, Materials Science (cond-mat.mtrl-sci), 021001 nanoscience & nanotechnology, Semiconductor, symbols, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, business, Raman spectroscopy
Abstract: International audience; Electronic properties and lattice dynamics of bulk ɛ-GaSe and one, two, and three tetralayers GaSe are investigated by means of density functional and density functional perturbation theory. The few-tetralayer systems are semiconductors with an indirect nature of the fundamental band gap and a Mexican-hat shape is observed at the top of the valence band. The phonon branch analysis reveals the dynamical stability for all systems considered together with the LO-TO splitting breakdown in two-dimensional systems. In-plane (E) and out-of-plane (A) zone-center lattice vibrations dominate the Raman and IR spectra.
Published: 2019
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10. A simple position operator for periodic systems

Author: Stefano Battaglia, Diego Moreno, Stefano Evangelisti, Jorge Berger, Gian Luigi Bendazzoli, Emília Valença Ferreira de Aragão, Nicolas Suaud, Thierry Leininger, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Università degli Studi di Perugia (UNIPG), Alma Mater Studiorum Università di Bologna [Bologna] (UNIBO), Systèmes étendus et magnétisme (LCPQ) (SEM), European Theoretical Spectroscopy Facility (ETSF), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
Subjects: Physics, Operator (physics), Mathematical analysis, Position operator, FOS: Physical sciences, 02 engineering and technology, Expression (computer science), 021001 nanoscience & nanotechnology, 01 natural sciences, Condensed Matter - Other Condensed Matter, Simple (abstract algebra), [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Thermodynamic limit, Key (cryptography), Periodic boundary conditions, Tensor, 010306 general physics, 0210 nano-technology, Other Condensed Matter (cond-mat.other)
Abstract: We present a position operator that is compatible with periodic boundary conditions (PBC). It is a one-body operator that can be applied in calculations of correlated materials by simply replacing the traditional position vector by the new definition. We show that it satisfies important fundamental as well as practical constraints. To illustrate the usefulness of the PBC position operator we apply it to the localization tensor, a key quantity that is able to differentiate metallic from insulating states. In particular, we show that the localization tensor given in terms of the PBC position operator yields the correct expression in the thermodynamic limit. Moreover, we show that it correctly distinguishes between finite precursors of metals and insulators., 5 pages, 1 figure
Published: 2019
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11. Distributed Gaussian orbitals for the description of electrons in an external potential

Author: Léa Brooke, Nicolas Suaud, Pierre-François Loos, Stefano Evangelisti, Alejandro Diaz-Marquez, Thierry Leininger, J. A. Berger, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Systèmes étendus et magnétisme (LCPQ) (SEM), European Theoretical Spectroscopy Facility (ETSF), Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3)
Subjects: Physics, Work (thermodynamics), Gaussian, Organic Chemistry, Electron, 010402 general chemistry, 01 natural sciences, Quantum chemistry, Catalysis, 0104 chemical sciences, Computer Science Applications, Inorganic Chemistry, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, symbols.namesake, Computational Theory and Mathematics, Atomic orbital, 0103 physical sciences, symbols, Statistical physics, Physical and Theoretical Chemistry, 010306 general physics, Basis set, ComputingMilieux_MISCELLANEOUS
Abstract: In this work, we demonstrate the viability of using distributed Gaussian orbitals as a basis set for the calculation of the properties of electrons subjected to an external potential. We validate our method by studying one-electron systems for which we can compare to exact analytical results. We highlight numerical aspects that require particular care when using a distributedGaussian basis set. In particular, we discuss the optimal choice for the distance between two neighboring Gaussian orbitals. Finally, we show how our approach can be applied to many-electron problems.
Published: 2018
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12. TDDFT, excitations and spectroscopy

Author: Olevano, Valerio, Théorie de la Matière Condensée (TMC ), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), European Theoretical Spectroscopy Facility (ETSF), Dominik Schaniel, and Theo Woike
Subjects: time-dependent, optical absorption, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, spectroscopy, EELS, TDDFT, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], electronic excitations, IXSS, TDLDA, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018
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13. Classical and ab Initio Plasmonics Meet at Sub-nanometric Noble Metal Rods

Author: Frank Rabilloud, Hans-Christian Weissker, Antonio I. Fernández-Domínguez, P. García-González, Rajarshi Sinha-Roy, Centre Interdisciplinaire de Nanoscience de Marseille (CINaM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), European Theoretical Spectroscopy Facility (ETSF), new, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)
Subjects: Electromagnetics, Ab initio, 02 engineering and technology, engineering.material, 010402 general chemistry, 01 natural sciences, Physics::Atomic and Molecular Clusters, Electrical and Electronic Engineering, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Plasmon, Physics, Mesoscopic physics, Condensed matter physics, Time-dependent density functional theory, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, engineering, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Nanorod, Noble metal, Absorption (chemistry), 0210 nano-technology, Biotechnology
Abstract: Applications of noble metal clusters and nanoparticles in different size ranges abound, from a couple of atoms through mesoscopic sizes. Classical electromagnetics calculations are now employed on smaller and smaller sizes, creating an effervescent dynamic in fields such as plasmonics and approaching the tiny sizes where quantum effects and the atomistic structure of matter play predominant roles. Nonetheless, explicit demonstrations of their merits and limitations are rare. Here we study the optical absorption of subnanometric elongated coinage-metal particles using ab initio and classical electromagnetics methods. The comparison between both approaches reveals that the classical plasmonic frequencies are in astonishing agreement with those predicted by ab initio theory for atomistic three-dimensional rods and quasi-one-dimensional chains, as long as collective surface-plasmon resonances lie far below the onset of d-electron excitations. The physical origin of this striking agreement is clarified through...
Published: 2017
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14. Interpretation of monoclinic hafnia valence electron energy-loss spectra by time-dependent density functional theory

Author: Linda Hung, C. Guedj, N. Bernier, P. Blaise, Valerio Olevano, Francesco Sottile, European Theoretical Spectroscopy Facility (ETSF), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Théorie de la Matière Condensée (NEEL - TMC), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), GENCI-IDRIS, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and Théorie de la Matière Condensée (TMC )
Subjects: monoclinic, EELS, 02 engineering and technology, Electronic structure, Electron, 7. Clean energy, 01 natural sciences, Molecular physics, DFT, Spectral line, HfO 2, TDDFT, 0103 physical sciences, 010306 general physics, Plasmon, VEELS, Physics, Condensed matter physics, PACS: 77.22.Ch, 79.20.Uv, 71.15.Mb, 71.15.Qe, Time-dependent density functional theory, 021001 nanoscience & nanotechnology, hafnia, Quasiparticle, Density of states, TEM, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, Valence electron
Abstract: International audience; We present the valence electron energy-loss spectrum and the dielectric function of monoclinic hafnia (m-HfO$_2$) obtained from time-dependent density-functional theory (TDDFT) predictions and compared to energy-filtered spectroscopic imaging measurements in a high-resolution transmission-electron microscope. Fermi's Golden Rule density-functional theory (DFT) calculations can capture the qualitative features of the energy-loss spectrum, but we find that TDDFT, which accounts for local-field effects, provides nearly quantitative agreement with experiment. Using the DFT density of states and TDDFT dielectric functions, we characterize the excitations that result in the m-HfO$_2$ energy loss spectrum. The sole plasmon occurs between 13-16 eV, although the peaks $\sim$28 and above 40 eV are also due to collective excitations. We furthermore elaborate on the first-principles techniques used, their accuracy, and remaining discrepancies among spectra. More specifically, we assess the influence of Hf semicore electrons (5$p$ and 4$f$) on the energy-loss spectrum, and find that the inclusion of transitions from the 4$f$ band damps the energy-loss intensity in the region above 13 eV. We study the impact of many-body effects in a DFT framework using the adiabatic local-density approximation (ALDA) exchange-correlation kernel, as well as from a many-body perspective using a $GW$-derived electronic structure to account for self-energy corrections. These results demonstrate some cancellation of errors between self-energy and excitonic effects, even for excitations from the Hf $4f$ shell. We also simulate the dispersion with increasing momentum transfer for plasmon and collective excitation peaks.
Published: 2016
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15. Towards time-dependent current-density-functional theory in the non-linear regime

Author: J. M. Escartín, Phuong Mai Dinh, Paul-Gerhard Reinhard, Eric Suraud, Marc Vincendon, Pina Romaniello, Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge [UK] (CAM)-University of Cambridge [UK] (CAM), Systèmes de Fermions Finis - Agrégats (LPT), Laboratoire de Physique Théorique (LPT), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Institut für Theoretische Physik, Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Apollo - University of Cambridge Repository
Subjects: [PHYS]Physics [physics], Chemistry, General Physics and Astronomy, Time-dependent density functional theory, Moment (mathematics), Nonlinear system, Quantum mechanics, 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics, Density functional theory, Time domain, Statistical physics, Relaxation (approximation), Physical and Theoretical Chemistry, Local-density approximation, Adiabatic process, ComputingMilieux_MISCELLANEOUS
Abstract: Time-Dependent Density-Functional Theory (TDDFT) is a well-established theoretical approach to describe and understand irradiation processes in clusters and molecules. However, within the so-called adiabatic local density approximation (ALDA) to the exchange-correlation (xc) potential, TDDFT can show insufficiencies, particularly in violently dynamical processes. This is because within ALDA the xc potential is instantaneous and is a local functional of the density, which means that this approximation neglects memory effects and long-range effects. A way to go beyond ALDA is to use Time-Dependent Current-Density-Functional Theory (TDCDFT), in which the basic quantity is the current density rather than the density as in TDDFT. This has been shown to offer an adequate account of dissipation in the linear domain when the Vignale-Kohn (VK) functional is used. Here, we go beyond the linear regime and we explore this formulation in the time domain. In this case, the equations become very involved making the computation out of reach; we hence propose an approximation to the VK functional which allows us to calculate the dynamics in real time and at the same time to keep most of the physics described by the VK functional. We apply this formulation to the calculation of the time-dependent dipole moment of Ca, Mg and Na2. Our results show trends similar to what was previously observed in model systems or within linear response. In the non-linear domain, our results show that relaxation times do not decrease with increasing deposited excitation energy, which sets some limitations to the practical use of TDCDFT in such a domain of excitations.
Published: 2015
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16. Quasiparticle excitations in the photoemission spectrum of CuO from first principles: A GW study

Author: C. Rödl, Lucia Reining, Francesco Sottile, European Theoretical Spectroscopy Facility (ETSF), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: Materials science, Condensed matter physics, Condensed Matter::Superconductivity, Spectrum (functional analysis), Quasiparticle, Strongly correlated material, Condensed Matter::Strongly Correlated Electrons, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Condensed Matter Physics, Electronic, Optical and Magnetic Materials
Abstract: International audience; We present ab initio quasiparticle calculations for electronic excitations and the fundamental band gap of the strongly correlated transition-metal oxide CuO using the GW approximation of many-body perturbation theory. Problems related to the suitability of the method for strongly correlated materials and issues of self-consistency are addressed. We explain why quasiparticle self-consistent GW strongly overestimates the band gap of CuO. Apart from the band gap, electron addition and removal spectra in the quasiparticle approximation including lifetime and matrix-element effects are found to be in excellent agreement with the quasiparticle excitations in direct and inverse photoemission data.
Published: 2015
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17. Interplay between structure and electronic properties of layered transition-metal dichalcogenides: Comparing the loss function of 1T and 2H polymorphs

Author: Cudazzo, Pierluigi, Gatti, Matteo, Rubio, Angel, Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Theoretical Spectroscopy Facility (ETSF), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Fritz-Haber-Institut der Max-Planck-Gesellschaft (FHI), Max Planck Society, Ministerio de Economía y Competitividad (España), Universidad del País Vasco, Eusko Jaurlaritza, European Research Council, European Commission, CEIT and Tecnun, Universidad de Navarra [Pamplona] (UNAV), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: Exciton dispersion, Two-dimensional materials, Exciton dispersion, Bethe-Salpeter equations, Bethe-Salpeter equations, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Two-dimensional materials
Abstract: Transition-metal dichalcogenides (TMD) share the same global layered structure, but distinct polymorphs are characterized by different local coordinations of the transition-metal atoms. Here we compared the 1T and 2H families of metallic TMD, both in the bulk and in the two-dimensional forms. By means of first-principles time-dependent density functional calculations of the loss function, we established the direct connection between the low-energy plasmon properties and the crystal-structure symmetry. The different atomic environments affect the d−d electron-hole excitations, which are prominent at low energies, resulting in distinct in-plane plasmon dispersions in the two families. Conversely, the different periodicity of the plasmon reappearance along the c axis perpendicular to the layers can be used to distinguish the various crystal structures of TMD., We acknowledge financial support from the European Research Council Advanced grant DYNamo (Grant No. ERC- 2010-AdG-267374), Spanish grant (Grant No. 2010-21282-C02-01), Grupos Consolidados UPV/EHU del Gobierno Vasco (Grant No. IT578-13), and European Commission project CRONOS (Grant No. 280879-2). This research was also supported by a Marie Curie FP7 Integration Grant within the Seventh European Union Framework Programme.
Published: 2014
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18. Solution to the many-body problem in one point

Author: Lucia Reining, Falk Tandetzky, Bernardo S. Mendoza, Pina Romaniello, Christian Brouder, Jorge Berger, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Systèmes de Fermions Finis - Agrégats (LPT), Laboratoire de Physique Théorique (LPT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), Max Planck Institute of Microstructure Physics, Centro de Investigaciones en Óptica, Centro de Investigaciones en Optica, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones en Optica (CIO), Consejo Nacional de Ciencia y Tecnología [Mexico] (CONACYT), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées
Subjects: Physics, [PHYS]Physics [physics], Work (thermodynamics), 010304 chemical physics, General Physics and Astronomy, Function (mathematics), 01 natural sciences, Many-body problem, Set (abstract data type), Scheme (mathematics), Quantum mechanics, Ordinary differential equation, 0103 physical sciences, Applied mathematics, Functional derivative, Point (geometry), 010306 general physics
Abstract: In this work we determine the one-body Greenʼs function as solution of a set of functional integro-differential equations, which relate the one-particle Greenʼs function to its functional derivative with respect to an external potential. In the same spirit as Lani et al (2012 New J. Phys. 14 013056), we do this in a one-point model, where the equations become ordinary differential equations (DEs) and, hence, solvable with standard techniques. This allows us to analyze several aspects of these DEs as well as of standard methods for determining the one-body Greenʼs function that are important for real systems. In particular: (i) we present a strategy to determine the physical solution among the many mathematical solutions; (ii) we assess the accuracy of an approximate DE related to the +cumulant method by comparing it to the exact physical solution and to standard approximations such as ; (iii) we show that the solution of the approximate DE can be improved by combining it with a screened interaction in the random-phase approximation. (iv) We demonstrate that by iterating the Dyson equation one does not always converge to a solution and we discuss which iterative scheme is the most suitable to avoid such errors.
Published: 2014
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19. Erratum: Solution to the many-body problem in one point

Author: Berger, Arjan, Romaniello, Pina, Tandetzky, Falk, Mendoza, Bernardo S, Brouder, Christian, Reining, Lucia, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC), Systèmes de Fermions Finis - Agrégats (LPT), Laboratoire de Physique Théorique (LPT), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, European Theoretical Spectroscopy Facility (ETSF), Max Planck Institute of Microstructure Physics, Centro de Investigaciones en Óptica, Centro de Investigaciones en Optica, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Centro de Investigaciones en Optica (CIO), Consejo Nacional de Ciencia y Tecnología [Mexico] (CONACYT), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics]
Abstract: International audience; In this work we determine the one-body Greenʼs function as solution of a set of functional integro-differential equations, which relate the one-particle Greenʼs function to its functional derivative with respect to an external potential. In the same spirit as Lani et al (2012 New J. Phys. 14 013056), we do this in a one-point model, where the equations become ordinary differential equations (DEs) and, hence, solvable with standard techniques. This allows us to analyze several aspects of these DEs as well as of standard methods for determining the one-body Greenʼs function that are important for real systems. In particular: (i) we present a strategy to determine the physical solution among the many mathematical solutions; (ii) we assess the accuracy of an approximate DE related to the $GW$+cumulant method by comparing it to the exact physical solution and to standard approximations such as $GW$; (iii) we show that the solution of the approximate DE can be improved by combining it with a screened interaction in the random-phase approximation. (iv) We demonstrate that by iterating the $GW$ Dyson equation one does not always converge to a $GW$ solution and we discuss which iterative scheme is the most suitable to avoid such errors.
Published: 2014
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20. Quasiparticle Self-Consistent GW Method for the Spectral Properties of Complex Materials

Author: Bruneval, Fabien, Gatti, Matteo, Service de recherches de métallurgie physique (SRMP), Département des Matériaux pour le Nucléaire (DMN), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Electronic structure, paper, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Ab initio calculations, GW approximation, Many-body perturbation t heory
Abstract: International audience; The GW approximation to the formally exact many-body perturbation theory has been applied successfully to materials for several decades. Since the practical calculations are extremely cumbersome, the GW self-energy is most commonly evaluated using a first-order perturbative approach: This is the so-called G 0 W 0 scheme. However, the G 0 W 0 approximation depends heavily on the mean-field theory that is employed as a basis for the perturbation theory. Recently, a procedure to reach a kind of self-consistency within the GW framework has been proposed. The quasiparticle self-consistent GW (QSGW) approximation retains some positive aspects of a self-consistent approach, but circumvents the intricacies of the complete GW theory, which is inconveniently based on a non-Hermitian and dynamical self-energy. This new scheme allows one to surmount most of the flaws of the usual G 0 W 0 at a moderate calculation cost and at a reasonable implementation burden. In particular, the issues of small band gap semiconductors, of large band gap insulators, and of some transition metal oxides are then cured. The QSGW method broadens the range of materials for which the spectral properties can be predicted with confidence.
Published: 2014
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21. Photoemission spectra and effective masses of n- and p-type oxide semiconductors from first principles: ZnO, CdO, SnO2, MnO, and NiO

Author: Rödl, Claudia, Schleife, André, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Condensed Matter and Materials Division, and Lawrence Livermore National Laboratory (LLNL)
Subjects: [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other]
Abstract: International audience; While there is a persistent interest in oxides, e.g., for semiconductor technology or optoelectronics, it seems to be difficult to achieve n-type and p-type doping for one and the same material. At the same time, it is important to understand the electronic structure for both types of doping individually. In this work, we use modern electronic-structure calculations to compute the density of states as well as effective electron and hole masses for n-type (ZnO, CdO, SnO2) and p-type (MnO, NiO) oxide materials. We establish our ab initio electronic structures by comparison to photoemission experiments at various incident photon energies. Taking into account the photoionization cross-sections, we are able to analyze the contributions of different atomic states and to verify the results by comparison to measured data. Based on these electronic structures, we calculate free-electron and free-hole masses as well as their dependence on the concentration of free carriers in the system. For SnO2, we compare with experimental results from another article (see M. Feneberg et al., Phys. Status Solidi A, DOI 10.1002/pssa.201330147 (2013) ) in this special issue. (C) 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Published: 2014
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22. Multiple satellites in materials with complex plasmon spectra: From graphite to graphene

Author: John J. Rehr, Francesco Sottile, Lorenzo Sponza, Mathieu G. Silly, Joshua J. Kas, Debora Pierucci, Lucia Reining, Christine Giorgetti, Fausto Sirotti, Matteo Guzzo, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Department of Physics, University of Washington, Okayama University, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: Physics, Graphene, Photon energy, Condensed Matter Physics, Spectral line, Electronic, Optical and Magnetic Materials, law.invention, law, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Quasiparticle, Physics::Atomic and Molecular Clusters, Satellite, Graphite, Atomic physics, Plasmon, Energy (signal processing)
Abstract: The photoemission spectrum of graphite is still debated. To help resolve this issue, we present photoemission measurements at high photon energy and analyze the results using a Green's function approach that takes into account the full complexity of the loss spectrum. Our measured data show multiple satellite replicas. We demonstrate that these satellites are of intrinsic origin, enhanced by extrinsic losses. The dominating satellite is due to the $\ensuremath{\pi}+\ensuremath{\sigma}$ plasmon of graphite, whereas the $\ensuremath{\pi}$ plasmon creates a tail on the high-binding energy side of the quasiparticle peak. The interplay between the two plasmons leads to energy shifts, broadening, and additional peaks in the satellite spectrum. We also predict the spectral changes in the transition from graphite towards graphene.
Published: 2014
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23. Evidence for anisotropic dielectric properties of monoclinic hafnia using high-resolution TEM valence electron energy-loss spectroscopy and ab initio time-dependent density-functional theory

Author: Guedj, Cyril, Hung, Linda, Zobelli, Alberto, Blaise, Philippe, Sottile, Francesco, Olevano, Valerio, Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information (CEA-LETI), Direction de Recherche Technologique (CEA) (DRT (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Théorie de la Matière Condensée (TMC), Institut Néel (NEEL), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF), GENCI project i2012096-655 and 544, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Théorie de la Matière Condensée (NEEL - TMC), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)
Subjects: Condensed Matter - Materials Science, EELS, ab initio, Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, anisotropy, HR-TEM, Condensed Matter::Materials Science, energy-loss, plasmon, TDDFT, hafnia, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], TEM, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], VEELS, HfO2
Abstract: The effect of nanocrystal orientation on the energy loss spectra of monoclinic hafnia (m-HfO$_2$) is measured by high resolution transmission electron microscopy (HRTEM) and valence energy loss spectroscopy (VEELS) on high quality samples. For the same momentum-transfer directions, the dielectric properties are also calculated ab initio by time-dependent density-functional theory (TDDFT). Experiments and simulations evidence anisotropy in the dielectric properties of m-HfO$_2$, most notably with the direction-dependent oscillator strength of the main bulk plasmon. The anisotropic nature of m-HfO$_2$ may contribute to the differences among VEELS spectra reported in literature. The good agreement between the complex dielectric permittivity extracted from VEELS with nanometer spatial resolution, TDDFT modeling, and past literature demonstrates that the present HRTEM-VEELS device-oriented methodology is a possible solution to the difficult nanocharacterization challenges given in the International Technology Roadmap for Semiconductors., 5 pages, 3 figures
Published: 2014
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24. Supercritical carbon dioxide extraction of metals from sulphuric acid solutions

Author: Hung, L., Hertz, Audrey, Hatmann, D., Charton, F., Boutin, Olivier, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), Institut Européen des membranes (IEM), Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Constant, Eddy, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), and Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)
Subjects: [SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; no abstract
Published: 2014

25. Giving credit where credit is due: The Stone-(Thrower)-Wales designation revisited

Author: Jean-Christophe Charlier, Marc Monthioux, Centre d'élaboration de matériaux et d'études structurales (CEMES), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), Unité de Physico-Chimie et de Physique des Matériaux (PCPM), Université Catholique de Louvain = Catholic University of Louvain (UCL)-European Theoretical Spectroscopy Facility (ETSF), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Near field microscopy, [PHYS]Physics [physics], Materials science, Human being, 02 engineering and technology, General Chemistry, Nano-carbon, 010402 general chemistry, 021001 nanoscience & nanotechnology, Graphene lattices, 01 natural sciences, Carbon, 0104 chemical sciences, General Materials Science, Aberration-corrected, Nanoforms, 0210 nano-technology, Transmission electron microscopy
Abstract: cited By 10; International audience; Naming things is a fundamental factor in communication between human beings. One might think that considering something now to be correct, when it clearly does not conform to the original meaning is a pity. Languages are in constant evolution, new words are always being created and new meanings appear, but what is important is that the same word is understood by everyone as designating the same thing. To give an example within the scope of this journal, the often unique properties and performance of carbon nanoforms have attracted many scientists whose background is not carbon-related, and this has induced a multiplication of the irrelevant use of terms whose meaning was clear and universally shared within the carbon community before the Nobel-recognized nanocarbon saga started. Now that the graphene lattice can be directly imaged by means of near-field microscopy or aberration-corrected transmission electron microscopy, such a model looks definitely unrealistic.
Published: 2014
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26. Loss spectroscopy of molecular solids: combining experiment and theory

Author: Roth, F., Cudazzo, P., Mahns, B., Gatti, M., Bauer, J., Hampel, S., Nohr, M., Berger, H., Knupfer, M., Rubio, A., Leibniz Institute for Solid State and Materials Research (IFW Dresden), Leibniz Association, Deutsches Elektronen-Synchrotron [Zeuthen] (DESY), Helmholtz-Gemeinschaft = Helmholtz Association, Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Fritz-Haber-Institut der Max-Planck-Gesellschaft (FHI), Max Planck Society, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], ddc:530, [SPI.MECA]Engineering Sciences [physics]/Mechanics [physics.med-ph]
Abstract: International audience; The nature of the lowest-energy electronic excitations in prototypical molecular solids is studied here in detail by combining electron energy loss spectroscopy (EELS) experiments and state-of-the-art many-body calculations based on the Bethe-Salpeter equation. From a detailed comparison of the spectra in picene, coronene and tetracene we generally find a good agreement between theory and experiment, with an upshift of the main features of the calculated spectrum of 0.1-0.2 eV, which can be considered the error bar of the calculation. We focus on the anisotropy of the spectra, which illustrates the complexity of this class of materials, showing a high sensitivity with respect to the three-dimensional packing of the molecular units in the crystal. The differences between the measured and the calculated spectra are explained in terms of the small differences between the crystal structures of the measured samples and the structural model used in the calculations. Finally, we discuss the role played by the different electron-hole interactions in the spectra. We thus demonstrate that the combination of highly accurate experimental EELS and theoretical analysis is a powerful tool to elucidate and understand the electronic properties of molecular solids.
Published: 2013
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27. Local-field effects on the plasmon dispersion of two-dimensional transition metal dichalcogenides

Author: Cudazzo, Pierluigi, Gatti, Matteo, Rubio, Angel, Nano-Bio Spectroscopy group (nanobio), CSIC-UPV/EHU-MPC and DIPC, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), CEIT and Tecnun, Universidad de Navarra [Pamplona] (UNAV), Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Fritz-Haber-Institut der Max-Planck-Gesellschaft (FHI), and Max Planck Society
Subjects: [PHYS]Physics [physics], Condensed Matter - Materials Science, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Materials Science (cond-mat.mtrl-sci), FOS: Physical sciences, Physics::Optics, matériaux bi-dimensionnels, [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], Dichalcogénures, dispersion du plasmon, matériaux bi-dimensionnels, dispersion du plasmon, Dichalcogénures
Abstract: Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence., Two-dimensional (2D) transition-metal dichalcogenides (TMDs) are gaining increasing attention as an alternative to graphene for their very high potential in optoelectronics applications. Here, we consider two prototypical metallic 2D TMDs, NbSe2 and TaS2. Using a first-principles approach, we investigate the properties of the localized intraband d plasmon that cannot be modeled on the basis of the homogeneous electron gas. Finally, we discuss the effects of the reduced dimensionality on the plasmon dispersion through the interplay between the interband transitions and the local-field effects. This result can be exploited to tune the plasmonic properties of these novel 2D materials., We acknowledge financial support from the European Research Council Advanced Grant DYNamo (ERC-2010-AdG-267374), Spanish Grants (2010-21282-C02-01 and PIB2010US-00652), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT578-13) and European Commission projects CRONOS (grant number 280879-2 CRONOS CP-FP7). Computational time was granted by BSC Red Espanola de Supercomputacion and GENCI (project number 544).
Published: 2013
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28. Frenkel versus charge-transfer exciton dispersion in molecular crystals

Author: Matteo Gatti, Pierluigi Cudazzo, Francesco Sottile, Angel Rubio, Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Fritz-Haber-Institut der Max-Planck-Gesellschaft (FHI), Max Planck Society, Spectroscopie théorique (ST), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), LSI - Spectroscopie théorique (ST), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Condensed Matter::Quantum Gases, 010304 chemical physics, Condensed matter physics, Condensed Matter::Other, Exciton, Exchange interaction, Momentum transfer, Electron, Condensed Matter Physics, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 01 natural sciences, Electronic, Optical and Magnetic Materials, Pentacene, Delocalized electron, chemistry.chemical_compound, Condensed Matter::Materials Science, chemistry, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Dispersion (optics), 010306 general physics, Wave function
Abstract: By solving the many-body Bethe-Salpeter equation at finite momentum transfer, we characterize the exciton dispersion in two prototypical molecular crystals, picene and pentacene, in which localized Frenkel excitons compete with delocalized charge-transfer excitons. We explain the exciton dispersion on the basis of the interplay between electron and hole hopping and electron-hole exchange interaction, unraveling a simple microscopic description to distinguish Frenkel and charge-transfer excitons. This analysis is general and can be applied to other systems in which the electron wave functions are strongly localized, as in strongly correlated insulators., The authors acknowledge financial support from the European Research Council Advanced Grant DYNamo (ERC-2010-AdG-267374), Spanish grants (2010-21282-C02-01 and PIB2010US-00652), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT578-13), European Commission projects CRONOS (Grant No. 280879-2 CRONOS CP-FP7), and the Maison de la simulation for technical support. Computational time was granted by GENCI (Project No. 544) and by the CNANO-SIMULEE-2009 project. This work was carried out under the HPC-EUROPA2 project, with the support of the European Community–Research Infrastructure Action of the FP7
Published: 2013
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29. Exciton dispersion from first principles

Author: Matteo Gatti, Francesco Sottile, European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: Physics, Scattering, Electron energy loss spectroscopy, Exciton, Momentum transfer, Ab initio, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Delocalized electron, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Atomic physics, 010306 general physics, 0210 nano-technology, Electronic band structure, Biexciton
Abstract: We present a scheme to calculate exciton dispersions in real materials that is based on the first-principles many-body Bethe-Salpeter equation. We assess its high level of accuracy by comparing our results for LiF with recent inelastic x-ray scattering experimental data on a wide range of energy and momentum transfer. We show its great analysis power by investigating the role of the different electron-hole interactions that determine the exciton band structure and the peculiar “exciton revival” at large momentum transfer. Our calculations for solid argon are a prediction and a suggestion for future experiments. These results demonstrate that the first-principles Bethe-Salpeter equation is able to describe the dispersion of localized and delocalized excitons on equal footing and represent a key step for the ab initio study of the exciton mobility., We acknowledge financial support from Triangle de la Physique 2013-0013T IXST, the ERC Advanced Grant DYNamo (No. ERC-2010-AdG-267374), Spanish Grants (No. 2010-21282-C02-01 and No. PIB2010US-00652),Grupos Consolidados UPV/EHU del GobiernoVasco (Grant No. IT578-13) and European Commission projects CRONOS (Grant No. 280879-2 CRONOS CP-FP7). Computational time was granted by GENCI (Project No. 544) and by the CNANO-SIMULEE-2009 project.
Published: 2013
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30. Mesures de solubilité en CO2 supercritique par méthode gravimétrique en dynamique

Author: Hung, L., Hertz, Audrey, Hartmann, Daniel, Charton, F., Boutin, Olivier, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), Institut Européen des membranes (IEM), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM), Institut de biologie et chimie des protéines [Lyon] (IBCP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Lavoisier Technique et Documentation, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Constant, Eddy
Subjects: [SPI.GPROC] Engineering Sciences [physics]/Chemical and Process Engineering, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, ComputingMilieux_MISCELLANEOUS
Abstract: National audience; no abstract
Published: 2013

31. Dynamical screening in correlated metals: Spectral properties of SrVO3 in the GW approximation and beyond

Author: Gatti, Matteo, Guzzo, Matteo, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), European Theoretical Spectroscopy Facility (ETSF), and European Theoretical Spectroscopy Facility
Subjects: [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Condensed Matter::Strongly Correlated Electrons, ComputingMilieux_MISCELLANEOUS
Abstract: SrVO3 is a prototypical strongly correlated metal. Here we interpret the signatures of electronic correlation measured in photoemission spectroscopy by combining the many-body GW approximation of the self-energy with an exponential representation of the Green's function. We explain those correlation effects as the consequence of the dynamical screening of the Coulomb interaction and the coupling between elementary excitations in the solid. Moreover we address the issue of satellites for empty states and discuss the possibility of plasmon-satellite series above the Fermi energy EF. In good agreement with experiment, we obtain from first principles the renormalization of the V 3d quasiparticle bands and the satellites close to EF that so far have been interpreted on the basis of the Hubbard model. Finally, we identify incoherent features due to dynamical correlation also at the bottom of the O 2p bands, beyond the traditional three-band Hubbard-model description. © 2013 American Physical Society., We acknowledge financial support fromANR(NT09-610745), the European Research Council Advanced Grant Dynamo (ERC-2010-AdG-267374), Spanish Grants (FIS2011-65702-C02-01 and PIB2010US-00652), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319-07), and European Commission project CRONOS (280879- 2).
Published: 2013
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32. Atomic and electronic properties of quasi-one-dimensional MoS2 nanowires

Author: Angel Rubio, Lucas Fernandez Seivane, Silvana Botti, Miguel A. L. Marques, Xóchitl López-Lozano, Hector Barron, UTSA Department of Physics and Astronomy [San Antonio], The University of Texas at San Antonio (UTSA), Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Donostia International Physics Center (DIPC), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), European Commission, Agence Nationale de la Recherche (France), Fundação para a Ciência e a Tecnologia (Portugal), Ministerio de Educación y Ciencia (España), Eusko Jaurlaritza, National Science Foundation (US), Universidad del País Vasco, University of Texas at San Antonio, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Nanostructure, Condensed matter physics, Mechanical Engineering, Ab initio, Nanowire, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Metal, Magnetization, Mechanics of Materials, Pairing, visual_art, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], visual_art.visual_art_medium, General Materials Science, Density functional theory, 0210 nano-technology, Saturation (magnetic)
Abstract: The structural, electronic, and magnetic properties of quasi-one-dimensional MoS2nanowires (NWs), passivated by extra sulfur, have been determined using ab initio density functional theory. The nanostructures were simulated using several different models based on experimental electron microscopy images and theoretical literature. It is found that independently of the geometrical details and the coverage of extra sulfur at the Mo edge, quasi-one-dimensional metallic states are predominant in all the low-energy model structures despite their reduced dimensionality. These metallic states are localized mainly at the edges. However, the electronic and magnetic character of the NWs does not depend only on the S saturation but also on the symmetry configuration of the S edge atoms. Our results show that for the same S saturation, the magnetization can be decreased by increasing the pairing of the S and Mo edge atoms. In spite of the observed pairing of S dimers at the Mo edge, the NWs do not experience a Peierls-like metal–insulator transition., This work was supported by the EU’s 7th Framework Program through the e-I3 contract ETSF (211956). X.L-L. and S.B. acknowledge funding by the ANR (Grant No. JC05 46741). M.A.L.M. acknowledges support from the Portuguese FCT (Grant No. PTDC/FIS/73578/2006) and from the French ANR (Grant No. ANR-08-CEXC8- 008-01). A.R. acknowledges funding by the Spanish MEC (Grant No. FIS2007-65702-C02-01), “Grupos Consolidados UPV/EHU del Gobierno Vasco” (Grant No. IT-319-07), NANO-ERA CHEMISTRY, Barcelona Supercomputing Center, “Red Española de Supercomputación,” and SGIker ARINA (UPV/EHU). L.F.S. and X.L-L. acknowledge the following funding: NSF-PREM DMR-0934218, UTSATRAC FY2011-2012.
Published: 2013
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33. Optical spectra of solids obtained by time-dependent density-functional theory with the jellium-with-gap model exchange-correlation kernel

Author: Valerio Olevano, Aleksandrs Terentjevs, Paolo E. Trevisanutto, Fabio Della Sala, Lucian A. Constantin, European Theoretical Spectroscopy Facility (ETSF), new, Théorie de la Matière Condensée (TMC), Institut Néel (NEEL), and Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)
Subjects: Solid-state physics, Jellium, Ab initio, FOS: Physical sciences, 02 engineering and technology, 01 natural sciences, Condensed Matter - Strongly Correlated Electrons, Condensed Matter::Materials Science, Quantum mechanics, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Perturbation theory, 010306 general physics, Electronic band structure, Physics, Condensed Matter - Materials Science, Strongly Correlated Electrons (cond-mat.str-el), Materials Science (cond-mat.mtrl-sci), Time-dependent density functional theory, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Condensed Matter - Other Condensed Matter, Self-energy, Kernel (statistics), [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology, Other Condensed Matter (cond-mat.other)
Abstract: Within the framework of ab initio time-dependent density-functional theory (TD-DFT), we propose a static approximation to the exchange-correlation kernel based on the jellium-with-gap model. This kernel accounts for electron-hole interactions and it is able to address both strongly bound excitons and weak excitonic effects. TD-DFT absorption spectra of several bulk materials (both semiconductor and insulators) are reproduced in very good agreement with the experiments and with a low computational cost., 5 pages, 3 figures, 1 table
Published: 2013
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34. Low-energy excitations in strongly correlated materials: A theoretical and experimental study of the dynamic structure factor in V2O3

Author: Iori, Federico, Rodolakis, Fanny, Gatti, Matteo, Reining, Lucia, Upton, M., Shvyd'ko, Y. V., Rueff, Jean-Pascal, Marsi, M., Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire de Physique des Solides (LPS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Advanced Photon Source [ANL] (APS), Argonne National Laboratory [Lemont] (ANL)-University of Chicago-US Department of Energy, Laboratoire de Chimie Physique - Matière et Rayonnement (LCPMR), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), European Project: 280879,EC:FP7:NMP,FP7-NMP-2011-SMALL-5,CRONOS(2012), European Project: 228539,EC:FP7:NMP,FP7-NMP-2008-SMALL-2,THEMA-CNT(2010), Argonne National Laboratory [Lemont] (ANL), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bruant, Gaëlle, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), and Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)
Subjects: [PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012
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35. Efficient calculation of the polarizability: a simplified effective-energy technique

Author: L. Reining, Jorge Berger, F. Sottile, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Physics, Work (thermodynamics), Solid-state physics, Complex system, 02 engineering and technology, Expression (computer science), 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Effective energy, Polarizability, Quantum mechanics, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Coulomb, Statistical physics, Reduced density matrix, 010306 general physics, 0210 nano-technology
Abstract: International audience; In a recent publication [J.A. Berger, L. Reining, F. Sottile, Phys. Rev. B 82, 041103(R) (2010)] we introduced the effective-energy technique to calculate in an accurate and numerically efficient manner the GW self-energy as well as the polarizability, which is required to evaluate the screened Coulomb interaction W. In this work we show that the effective-energy technique can be used to further simplify the expression for the polarizability without a significant loss of accuracy. In contrast to standard sum-over-state methods where huge summations over empty states are required, our approach only requires summations over occupied states. The three simplest approximations we obtain for the polarizability are explicit functionals of an independent- or quasi-particle one-body reduced density matrix. We provide evidence of the numerical accuracy of this simplified effective-energy technique as well as an analysis of our method.
Published: 2012
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36. Plasmon satellites in valence-band photoemission spectroscopy

Author: Guzzo, Matteo, Kas, Joshua J., Sottile, Francesco, Silly, Mathieu G., Sirotti, Fausto, Rehr, John J., Reining, Lucia, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Department of Physics, University of Washington, Okayama University, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Bruant, Gaëlle, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012

37. Feedback mechanism for the stability of the band gap of CuInSe2

Author: Levent Gütay, Alex Redinger, Yasuhiro Aida, Christiane Stephan, Sabina Caneva, Julien Vidal, Susan Schorr, David Regesch, Valérie Depredurand, Jes K. Larsen, Silvana Botti, Susanne Siebentritt, Laboratory for Photovoltaics Luxembourg, University of Luxembourg [Luxembourg], Crystallography Lab [Berlin], Helmholtz-Zentrum Berlin für Materialien und Energie GmbH (HZB), Physics Department, King‘s College London, Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: 010302 applied physics, Materials science, Band gap, 02 engineering and technology, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Stability (probability), Electronic, Optical and Magnetic Materials, Theoretical physics, Chemical physics, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, 0210 nano-technology, Mechanism (sociology), ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012
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38. Large crystal local-field effects in second-harmonic generation of a Si/CaF2 interface: An ab initio study

Author: Valérie Véniard, Matteo Bertocchi, Stefano Ossicini, Elena Degoli, E. Luppi, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), CNR-INFM and Dipartimento di Fisica, Università di Modena e Reggio Emilia, CNR-INFM and Dipartimento di Fisica, University of California [Berkeley] (UC Berkeley), University of California (UC), Centro S3, Istituto Nanoscienze [Modena] (CNR NANO), Dipartimento di Scienze e Metodi dell'Ingegneria [Reggio Emilia] (DISMI), Università degli Studi di Modena e Reggio Emilia = University of Modena and Reggio Emilia (UNIMORE), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Univ Calif Berkeley, Dept Chem, Berkeley, CA 94720 USA, affiliation inconnue, Università degli Studi di Modena e Reggio Emilia (UNIMORE), and Bruant, Gaëlle
Subjects: Materials science, Silicon, Interface (Java), Ab initio, Second-harmonic generation, chemistry.chemical_element, Condensed Matter Physics, Molecular physics, Electronic, Optical and Magnetic Materials, Crystal, chemistry, [PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], interfaces, second harmonic generation, DFT, Local field, Quantum well, ComputingMilieux_MISCELLANEOUS
Abstract: In this work we present the ab initio study of crystal local-field effects in second-harmonic generation spectroscopy for an interface material such as Si/CaF2. Starting from an independent particle picture, we demonstrate the fundamental importance of the polarization effects at the interface discontinuity. The estimation of the magnitude of crystal local-field effects for second-order nonlinear response in Si/CaF2 interface was done by a comparative study with the absorption spectroscopy in the linear response. In both cases, we observe that the microscopic fluctuations due to the inhomogeneities of the system cause a decrease of the intensities of the spectra. However, for second-harmonic generation the decrease is selective and completely inhomogeneous while for absorption it is almost rigid.We also compare our theoretical study with experimental data showing unambiguously that only when crystal local fields are included, it is possible to correctly interpret experimental results.
Published: 2012
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39. Novel Structural Motifs in Low Energy Phases of LiAlH4

Author: Silvana Botti, Maximilian Amsler, Stefan Goedecker, Tran Doan Huan, José A. Flores-Livas, Miguel A. L. Marques, Univ Basel, Dept Phys, CH-4056 Basel, Switzerland, affiliation inconnue, Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Department of Physics [Basel], University of Basel (Unibas), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Phonon, Ab initio, General Physics and Astronomy, Order (ring theory), 02 engineering and technology, 021001 nanoscience & nanotechnology, 01 natural sciences, Crystal structure prediction, Crystallography, Hydrogen storage, Phase (matter), [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Dehydrogenation, 010306 general physics, 0210 nano-technology, Energy (signal processing), ComputingMilieux_MISCELLANEOUS
Abstract: We identify a class of novel low energy phases of the hydrogen storage material ${\mathrm{LiAlH}}_{4}$ by using the ab initio minima hopping crystal structure prediction method. These phases are, unlike previous predictions and known structures of similar materials, characterized by polymeric networks consisting of Al atoms interlinked with H atoms. The most stable structure is a layered ionic crystal with $P{2}_{1}/c$ symmetry, and it has lower free energy than the previously reported structure over a wide range of temperatures. Furthermore, we carry out x-ray diffraction, phonon, and $GW$ band-structure analysis in order to characterize this phase. Its experimental synthesis would have profound implications for the study of dehydrogenation and rehydrogenation processes and the stability problem of ${\mathrm{LiAlH}}_{4}$ for hydrogen storage applications.
Published: 2012
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40. Efficient GW calculations for SnO2, ZnO, and rubrene: The effective-energy technique

Author: Berger, Arjan, Reining, Lucia, Sottile, Francesco, Groupe Méthodes et outils de la chimie quantique (LCPQ) (GMO), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other]
Abstract: International audience; In a recent Rapid Communication [ J. A. Berger, L. Reining and F. Sottile Phys. Rev. B 82 041103 (2010)], we presented the effective-energy technique to evaluate, in an accurate and numerically efficient manner, electronic excitations by reformulating spectral sum-over-states expressions such that only occupied states appear. In our approach all the empty states are accounted for by a single effective energy that can be obtained from first principles. In this work we provide further details of the effective-energy technique, in particular, when combined with the GW method, in which a huge summation over empty states appears in the calculation of both the screened Coulomb interaction and the self-energy. We also give further evidence of the numerical accuracy of the effective-energy technique by applying it to the technological important materials SnO2 and ZnO. Finally, we use this technique to predict the band gap of bulk rubrene, an organic molecular crystal with a 140-atom unit cell.
Published: 2012
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41. Crystalline and magnetic anisotropy of the 3d-transition metal monoxidesMnO, FeO, CoO, and NiO

Author: Schrön, A., Rödl, Claudia, Bechstedt, Friedhelm, Bruant, Gaëlle, Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität = Friedrich Schiller University Jena [Jena, Germany], European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Institut für Festkörpertheorie und-Optik, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: [PHYS.COND.CM-GEN] Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012

42. Valence Electron Photoemission Spectrum of Semiconductors: Ab Initio Description of Multiple Satellites

Author: Matteo Guzzo, Pina Romaniello, John J. Rehr, Joshua J. Kas, Matteo Gatti, Mathieu G. Silly, Giovanna Lani, Fausto Sirotti, Francesco Sottile, Lucia Reining, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Systèmes de Fermions Finis - Agrégats (LPT), Laboratoire de Physique Théorique (LPT), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Department of Physics, University of Washington, Okayama University, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), St Gobain R&D (091986), Triangle de la Physique (2007-71), DOE BES Grant DE-FG03-97ER45623, DOE CMCSN, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)
Subjects: GW approximation, Inverse photoemission spectroscopy, Ab initio, General Physics and Astronomy, FOS: Physical sciences, Angle-resolved photoemission spectroscopy, 02 engineering and technology, 7. Clean energy, 01 natural sciences, Secondary electrons, Spectral line, Condensed Matter - Strongly Correlated Electrons, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], 0103 physical sciences, Perturbation theory, 010306 general physics, Physics, Quantum Physics, Strongly Correlated Electrons (cond-mat.str-el), 021001 nanoscience & nanotechnology, Condensed Matter - Other Condensed Matter, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Atomic physics, 0210 nano-technology, Valence electron, Quantum Physics (quant-ph), Other Condensed Matter (cond-mat.other)
Abstract: PACS numbers: 71.45.Gm, 71.10. w, 71.15.Qe.-- et al., The experimental valence band photoemission spectrum of semiconductors exhibits multiple satellites that cannot be described by the GW approximation for the self-energy in the framework of many-body perturbation theory. Taking silicon as a prototypical example, we compare experimental high energy photoemission spectra with GW calculations and analyze the origin of the GW failure. We then propose an approximation to the functional differential equation that determines the exact one-body Green's function, whose solution has an exponential form. This yields a calculated spectrum, including cross sections, secondary electrons, and an estimate for extrinsic and interference effects, in excellent agreement with experiment. Our result can be recast as a dynamical vertex correction beyond GW, giving hints for further developments. © 2011 American Physical Society., We acknowledge support by ANR (NT09-610745), St Gobain R&D (091986), and Triangle de la Physique (2007-71). J.J.R. and J.J.K. are also supported in part by DOE BES Grant DE-FG03-97ER45623 and DOE CMCSN. Computer time was granted by IDRIS (544).
Published: 2011
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43. Crossover from adiabatic to antiadiabatic quantum pumping with dissipation

Author: Giuseppe E. Santoro, Carlotta Negri, Erio Tosatti, Nicola Manini, Franco Pellegrini, Fabio Pistolesi, Scuola Internazionale Superiore di Studi Avanzati / International School for Advanced Studies (SISSA / ISAS), Istituto Officina dei Materiali (CNR-IOM), National Research Council [Italy] (CNR), Laboratoire Ondes et Matière d'Aquitaine (LOMA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), Università degli Studi di Milano [Milano] (UNIMI), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), and Italian CNR through ESF Eurocore/FANAS/AFRI, by the Italian Ministry of University and Research, through PRIN/COFIN 20087NX9Y7
Subjects: Quantum decoherence, FOS: Physical sciences, General Physics and Astronomy, PACS numbers: 03.65.Yz, 03.65.Vf, 85.35.Be, 01 natural sciences, Settore FIS/03 - Fisica della Materia, 010305 fluids & plasmas, Pumping, Spin, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Quantum mechanics, Mesoscale and Nanoscale Physics (cond-mat.mes-hall), 0103 physical sciences, 010306 general physics, Adiabatic process, Quantum, Physics, Quantum Physics, Condensed Matter - Mesoscale and Nanoscale Physics, Dissipation, Adiabatic quantum computation, Condensed Matter - Other Condensed Matter, Quantum pump, Quantum theory, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], Dissipative system, Cooper pair, Quantum Physics (quant-ph), Other Condensed Matter (cond-mat.other), DC bias
Abstract: Quantum pumping, in its different forms, is attracting attention from different fields, from fundamental quantum mechanics, to nanotechnology, to superconductivity. We investigate the crossover of quantum pumping from the adiabatic to the anti-adiabatic regime in the presence of dissipation, and find general and explicit analytical expressions for the pumped current in a minimal model describing a system with the topology of a ring forced by a periodic modulation of frequency omega. The solution allows following in a transparent way the evolution of pumped DC current from much smaller to much larger omega values than the other relevant energy scale, the energy splitting introduced by the modulation. We find and characterize a temperature-dependent optimal value of the frequency for which the pumped current is maximal., 5 pages, 3 figures
Published: 2011
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44. Design of effective kernels for spectroscopy and molecular transport: Time-dependent current–density-functional theory

Author: Matteo Gatti, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Nano-Bio Spectroscopy Group, and Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU)
Subjects: Work (thermodynamics), General Physics and Astronomy, FOS: Physical sciences, 01 natural sciences, 7. Clean energy, 010305 fluids & plasmas, Condensed Matter - Strongly Correlated Electrons, 0103 physical sciences, Molecular Transport, Statistical physics, Physical and Theoretical Chemistry, Perturbation theory, 010306 general physics, Spectroscopy, density functional theory, Mathematics, perturbation theory, Strongly Correlated Electrons (cond-mat.str-el), many-body problems, Spectrum Analysis, exchange interactions (electron), Range (mathematics), Models, Chemical, Kernel (statistics), Quantum Theory, Functional theory, Current density
Abstract: 5 páginas., Time-dependent current–density-functional theory (TDCDFT) provides an, in principle, exact scheme to calculate efficiently response functions for a very broad range of applications. However, the lack of approximations valid for a range of parameters met in experimental conditions has so far delayed its extensive use in inhomogeneous systems. On the other side, in many-body perturbation theory accurate approximations are available, but at a price of a higher computational cost. In the present work, the possibility of combining the advantages of both approaches is exploited. In this way, an exact equation for the exchange-correlation kernel of TDCDFT is obtained, which opens the way for a systematic improvement of the approximations adopted in practical applications. Finally, an approximate kernel for an efficient calculation of spectra of solids and molecular conductances is suggested and its validity is discussed., Acknowledge the support from the European Union’s (EU’s) 7th framework program through the ETSF e-I3 infrastructure project (Grant No. 211956), the Spanish MEC (FIS2007-65702-C02-01), ACI Promociona (ACI2009-1036), Grupos Consolidados UPV/EHU del Gobierno Vasco (IT-319-07), and ETORTEK projects.
Published: 2011
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45. Double excitations in correlated systems: A many-body approach

Author: Sangalli, Davide, Romaniello, Pina, Onida, Giovanni, Marini, Andrea, CNISM, I-00146 Rome, Italy, CNISM, Dipartimento di Fisica, Università degli Studi di Milano [Milano] (UNIMI), Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, Università degli Studi di Roma Tor Vergata [Roma], IKERBASQUE, Basque Foundation for Science, Nano-Bio Spectroscopy Group, Universidad del Pais Vasco / Euskal Herriko Unibertsitatea [Espagne] (UPV/EHU), Università degli Studi di Milano = University of Milan (UNIMI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Ikerbasque - Basque Foundation for Science, and Romaniello, Pina
Subjects: STATES, PROPAGATOR, THEORY LINEAR-RESPONSE, EXCHANGE, ComputingMilieux_MISCELLANEOUS, APPROXIMATION
Abstract: International audience
Published: 2011

46. Théorie et Simulations numériques ab-initio des propriétés électroniques de nanostructures: vers la spectroscopie de perte d'énergie résolue spatialement

Author: Hambach, Ralf, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), new, Ecole Polytechnique X, Lucia Reining(Christine Giorgetti), and Hambach, R.
Subjects: ab-initio, carbon nanotubes, graphene, nanostructures, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], electron energy-loss spectroscopy, [PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], spectroscopie de perte d'énergie
Abstract: In this thesis, collective excitations of carbon systems with different dimensionality have been studied both theoretically and numerically. First, a method combining effective medium theory and ab-initio calculations has been developed which allows to describe the collective excitations of nanostructures (like carbon nanotubes) starting from the polarisability of their building blocks (graphene). In contrast to standard dielectric theory, the Maxwell equations are solved for the full frequency- and momentum-dependent microscopic dielectric function ε(q,q',ω) of the bulk material. The latter is calculated from first-principles within the Random Phase Approximation. Second, this method has been applied to calculate electron-energy loss spectra (EELS) for graphene and single-wall carbon nanotubes (SWCNT). The results are in good agreement with full ab-initio calculations of these systems and corresponding experiments. The linear dispersion of the π plasmon in graphene and SWCNTs has been analysed and explained. The directional dependence of the electron energy-loss spectra of SWCNTs is understood in terms of its normal mode excitations. Third, the use of ab-initio calculations for the prediction of spatially-resolved EELS is discussed. Therefore, the mixed dynamic form factor has been studied and a discontinuous behavior at certain Bragg reflections is predicted. This effect has been explained in terms of crystal local field effects and verified by IXS experiments on graphite and silicon. Finally, the building block approach is applied for spatially-resolved EELS., Cette thèse présente les résultats d'études théoriques et numériques des excitations collectives de systèmes de carbone de dimensionnalité différente. D'abord, une méthode combinant la théorie du milieu effectif et des calculs ab-initio a été développée pour décrire les excitations collectives de nanostructures (comme les nanotubes de carbone) à partir de la polarisabilité de leurs blocs élémentaires (graphène). Contrairement à la théorie diélectrique standard, les équations de Maxwell sont résolues pour la fonction diélectrique microscopique dépendant du temps et du moment ε(q,q',ω) du matériau massif. Cette dernière a été calculée à partir des premiers principes dans l'approximation de la phase aléatoire (RPA). Cette méthode a ensuite été appliquée pour calculer les spectres de perte d'énergie d'électrons (EELS) pour le graphène et les nanotubes de carbone monoparoi (SWCNT). L'accord avec les calculs complètement ab-initio sur ces systèmes et avec les expériences correspondantes est très bon. La dispersion du plasmon π dans le graphène et les SWCNT a été analysée et expliquée. La dépendance avec la direction du moment des spectres de perte d'énergie d'électrons des SWCNT est comprise en termes d'excitations des modes normaux. Finalement, l'utilisation des calculs ab-initio en vue de prédire le EELS résolu spatialement a été étudiée. Le facteur de forme mixte dynamique a été analysé et une discontinuité de son comportement pour certaines réflections de Bragg a été prédite. Cet effet a été expliqué par les effets de champ cristallin et a été confirmé par des expériences de IXS sur le graphite et le silicium. L'approche blocs élémentaires a été appliquée au EELS résolu spatialement.
Published: 2010

47. Momentum Distribution and Renormalization Factor in Sodium and the Electron Gas

Author: David M. Ceperley, Jeongnim Kim, Valerio Olevano, Arezki Issolah, J. Aleksi Soininen, Ken Esler, Tuomas Pylkkänen, Jeremy McMinis, Andrey Titov, Simo Huotari, Keijo Hämäläinen, Markus Holzmann, Nanophysique et Semiconducteurs (NPSC), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), Physics Department (UIUC), University of Illinois at Urbana-Champaign [Urbana], University of Illinois System-University of Illinois System, European Theoretical Spectroscopy Facility (ETSF), new, Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Théorie de la Matière Condensée (TMC), RTRA NanoSTAR, Fondation Nanosciences, Grenoble. GENCI, IDRIS, Nanophysique et Semiconducteurs (NEEL - NPSC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Théorie de la Matière Condensée (NEEL - TMC)
Subjects: Physics, Quantum Monte Carlo, Compton scattering, General Physics and Astronomy, FOS: Physical sciences, 02 engineering and technology, 021001 nanoscience & nanotechnology, 7. Clean energy, 01 natural sciences, Renormalization, Condensed Matter - Other Condensed Matter, Core electron, Quantum electrodynamics, [PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other], 0103 physical sciences, Quasiparticle, Wave vector, Condensed Matter::Strongly Correlated Electrons, 010306 general physics, 0210 nano-technology, Fermi gas, Fermi Gamma-ray Space Telescope, Other Condensed Matter (cond-mat.other)
Abstract: We present experimental and theoretical results on the momentum distribution and the quasiparticle renormalization factor in sodium. From an x-ray Compton-profile measurement of the valence-electron momentum density, we derive its discontinuity at the Fermi wavevector. This yields an accurate measure of the renormalization factor that we compare with quantum Monte Carlo and GW calculations performed both on crystalline sodium and on the homogeneous electron gas. Our calculated results are in good agreement with the experiment., 5 pages, 3 figures, 1 table
Published: 2010
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48. Ab initio calculations of electronic excitations: Collapsing spectral sums

Author: Lucia Reining, Francesco Sottile, Jorge Berger, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), European Theoretical Spectroscopy Facility (ETSF), European Theoretical Spectroscopy Facility, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)
Subjects: Physics, Band gap, Oxide, 02 engineering and technology, Advanced materials, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Electronic, Optical and Magnetic Materials, Power (physics), chemistry.chemical_compound, Effective energy, chemistry, Ab initio quantum chemistry methods, Simplicity (photography), 0103 physical sciences, Atomic physics, 010306 general physics, 0210 nano-technology, Order of magnitude
Abstract: International audience; We present a method for the evaluation of electronic excitations of advanced materials by reformulating spectral sum-over-states expressions such that only occupied states appear. All empty states are accounted for by one effective energy. Thus we keep the simplicity and precision of the sum-over-states approach while speeding up calculations by more than an order of magnitude. We demonstrate its power by applying it to the GW method, where a huge summation over empty states appears twice (screening and self-energy). The precision is shown for bulk Si and solid and atomic Ar. We then use it to determine the band gap of the technologically important oxide SnO2.
Published: 2010
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49. Nonlinear Optical Properties of Ni(Me(6)pzS(2))MX (M = Ni, Pd, Pt; X = Me(2)timdt, mnt)

Author: Pina Romaniello, M. D'Andria, Francesco Lelj, Laboratoire des Solides Irradiés (LSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), ETSF, European Theoretical Spectroscopy Facility, LaMI Dipartimento di Chimica and LaSCAMM, Università della Basilicata, European Theoretical Spectroscopy Facility (ETSF), and Università degli studi della Basilicata [Potenza] (UNIBAS)
Subjects: 010405 organic chemistry, Ligand, Hyperpolarizability, Porphyrazine, Electron, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, 3. Good health, Metal, chemistry.chemical_compound, Crystallography, Nonlinear optical, chemistry, Computational chemistry, Ab initio quantum chemistry methods, visual_art, visual_art.visual_art_medium, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; In this work we investigate the second-order response of complexes of formula Ni(Me6pzS2)MX (M = Ni, Pd, Pt; X = Me2timdt (monoanion of N,N′-disubstituted imidazolidine-2,4,5-trithione), mnt (maleonitriledithiolate)): by binding the porphyrazine to the metal−dithiolene, the electron asymmetry and π-conjugation of the latter is increased, and its second-order response can result enhanced. By performing ab initio calculations of the ground-state and response properties of these compounds, we predict the molecular first hyperpolarizability, we elucidate its electronic origin, and we illustrate its dependence on the metal and the dithiolene ligand. Our study indicates that these complexes show a very high second-order response, comparable to that of organic “push−pull” materials, and that the appropriate metal-dithiolene combination can significantly enhance it.
Published: 2010
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50. Ab initio high-energy excitonic effects in graphite and graphene

Author: Paolo E. Trevisanutto, Valerio Olevano, Markus Holzmann, Michel Côté, European Theoretical Spectroscopy Facility (ETSF), new, Laboratoire de physique et modélisation des milieux condensés (LPM2C), Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Théorie de la Matière Condensée (TMC), Institut Néel (NEEL), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS), ANR-05-BLAN-0191,ETSF-FRANCE,European Theoretical Spectroscopy Facility: création du centre français(2005), European Project, Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and Théorie de la Matière Condensée (NEEL - TMC)
Subjects: Ab initio, 02 engineering and technology, Electronic structure, 01 natural sciences, 7. Clean energy, Resonance (particle physics), law.invention, Condensed Matter::Materials Science, law, 0103 physical sciences, Physics::Atomic and Molecular Clusters, Continuum (set theory), Absorption (logic), Physics::Chemical Physics, 010306 general physics, Physics, Condensed matter physics, Graphene, Condensed Matter::Other, Bilayer, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Quasiparticle, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 0210 nano-technology
Abstract: We present ab initio many-body calculations of the optical absorption in bulk graphite, graphene and bilayer of graphene. Electron-hole interaction is included solving the Bethe-Salpeter equation on top of a $GW$ quasiparticle electronic structure. For all three systems, we observe strong excitonic effects at high energy, well beyond the continuum of $\ensuremath{\pi}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ensuremath{\ast}}$ transitions. In graphite, these affect the onset of $\ensuremath{\sigma}\ensuremath{\rightarrow}{\ensuremath{\sigma}}^{\ensuremath{\ast}}$ transitions. In graphene, we predict an excitonic resonance at 8.3 eV arising from a background continuum of dipole forbidden transitions. In the graphene bilayer, the resonance is shifted to 9.6 eV. Our results for graphite are in good agreement with experiments.
Published: 2010
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