20 results on '"Julien E, Rault"'
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2. Spin–Charge Interconversion in KTaO 3 2D Electron Gases
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Suvam Bhattacharya, Raphaël Salazar, Julien E. Rault, Jean-Philippe Attané, Guilhem Saiz, Manuel Bibes, Dmitri E. Nikonov, Ian A. Young, Patrick Le Fèvre, Anke Sander, Sara Varotto, François Bertran, Lin Chia-Ching, Paul Noël, Diogo C. Vaz, Felix Trier, Maxen Cosset-Cheneau, Luis M. Vicente-Arche, Nicolas Bergeal, Srijani Mallik, Laurent Vila, Julien Bréhin, Agnès Barthélémy, Hai Li, Gerbold Menard, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), SPINtronique et TEchnologie des Composants (SPINTEC), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), ANR-16-CE24-0017,TOP-RISE,Isolant topologique et etats d'interfaces Rashba pour l'électronique de spin(2016), ANR-19-CE47-0006,QUANTOP,Structures quantiques d'oxydes pour les dispositifs topologiques(2019), and ANR-18-CE24-0015,CORNFLAKE,Contrôle ferroélectrique du couplage spin-orbite dans les dichalcogenides de métaux de transition(2018)
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Materials science ,Magnetoresistance ,Condensed matter physics ,Photoemission spectroscopy ,Mechanical Engineering ,02 engineering and technology ,Electron ,Electronic structure ,Spin–orbit interaction ,021001 nanoscience & nanotechnology ,01 natural sciences ,Magnetic field ,T-symmetry ,Mechanics of Materials ,0103 physical sciences ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,General Materials Science ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,0210 nano-technology ,Perovskite (structure) - Abstract
International audience; Oxide interfaces exhibit a broad range of physical effects stemming from broken inversion symmetry. In particular, they can display non-reciprocal phenomena when time reversal symmetry is also broken, e.g., by the application of a magnetic field. Examples include the direct and inverse Edelstein effects (DEE, IEE) that allow the interconversion between spin currents and charge currents. The DEE and IEE have been investigated in interfaces based on the perovskite SrTiO$_3$ (STO), albeit in separate studies focusing on one or the other. The demonstration of these effects remains mostly elusive in other oxide interface systems despite their blossoming in the last decade. Here, we report the observation of both the DEE and IEE in a new interfacial two-dimensional electron gas (2DEG) based on the perovskite oxide KTaO$_3$. We generate 2DEGs by the simple deposition of Al metal onto KTaO$_3$ single crystals, characterize them by angle-resolved photoemission spectroscopy and magnetotransport, and demonstrate the DEE through unidirectional magnetoresistance and the IEE by spin-pumping experiments. We compare the spin-charge interconversion efficiency with that of STO-based interfaces, relate it to the 2DEG electronic structure, and give perspectives for the implementation of KTaO$_3$ 2DEGs into spin-orbitronic devices.
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- 2021
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3. Structure and electronic states of vicinal Ag(111) surfaces with densely kinked steps
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J Enrique Ortega, Guillaume Vasseur, Ignacio Piquero-Zulaica, Sonia Matencio, Miguel Angel Valbuena, Julien E Rault, Frederik Schiller, Martina Corso, Aitor Mugarza, and Jorge Lobo-Checa
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vicinal surface ,curved surface ,kinked step ,STM ,photoemission ,surface states ,Science ,Physics ,QC1-999 - Abstract
Vicinal surfaces exhibiting arrays of atomic steps are frequently investigated due to their diverse physical-chemical properties and their use as growth templates. However, surfaces featuring steps with a large number of low-coordinated kink-atoms have been widely ignored, despite their higher potential for chemistry and catalysis. Here, the equilibrium structure and the electronic states of vicinal Ag(111) surfaces with densely kinked steps are investigated in a systematic way using a curved crystal. With scanning tunneling microscopy we observe an exceptional structural homogeneity of this class of vicinals, reflected in the smooth probability distribution of terrace sizes at all vicinal angles. This allows us to observe, first, a subtle evolution of the terrace-size distribution as a function of the terrace-width that challenges statistical models of step lattices, and second, lattice fluctuations around resonant modes of surface states. As shown in angle resolved photoemission experiments, surface states undergo stronger scattering by fully-kinked step-edges, which triggers the full depletion of the two-dimensional band at surfaces with relatively small vicinal angles.
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- 2018
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4. Electronic band gap of van der Waals α-As2Te3 crystals
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Julien Chaste, Jean-Christophe Girard, Julien E. Rault, Jean-Francois Dayen, Gilles Patriarche, Fabrice Oehler, Demetrio Logoteta, Federico Bisti, Marco G. Pala, Charlie Gréboval, Abdelkarim Ouerghi, Debora Pierucci, Ulrich Nguétchuissi Noumbé, Emmanuel Lhuillier, Lama Khalil, Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), ALBA Synchrotron light source [Barcelone], Physico-chimie et dynamique des surfaces (INSP-E6), Institut des Nanosciences de Paris (INSP), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), ANR-19-CE09-0026,GRaSkop,Tuning Giant Rashba Spin-Orbit Coupling in Polar Single Layer Transition Metal Dichalcogenides(2019), ANR-18-CE24-0007,MAGICVALLEY,Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle(2018), ANR-17-CE24-0030,RhomboG,Propriétés electroniques de couches minces de graphite rhombohedrique(2017), European Project: 756225,blackQD, Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, lhuillier, emmanuel, Tuning Giant Rashba Spin-Orbit Coupling in Polar Single Layer Transition Metal Dichalcogenides - - GRaSkop2019 - ANR-19-CE09-0026 - AAPG2019 - VALID, APPEL À PROJETS GÉNÉRIQUE 2018 - Polarisation de vallée induite par couplage d'échange magnétique dans les matériaux 2D à grande échelle - - MAGICVALLEY2018 - ANR-18-CE24-0007 - AAPG2018 - VALID, Propriétés electroniques de couches minces de graphite rhombohedrique - - RhomboG2017 - ANR-17-CE24-0030 - AAPG2017 - VALID, and ERC blackQD - blackQD - 756225 - INCOMING
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Materials science ,Physics and Astronomy (miscellaneous) ,As2Te3 ,Scanning tunneling spectroscopy ,Stacking ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,symbols.namesake ,Scanning transmission electron microscopy ,Anisotropy ,Spectroscopy ,Field Effect Transistor ,Electronic Transport ,business.industry ,021001 nanoscience & nanotechnology ,Electronic Band Gap ,[PHYS.COND.CM-MS] Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,0104 chemical sciences ,Semiconductor ,Chemical physics ,symbols ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,van der Waals force ,Photonics ,0210 nano-technology ,business - Abstract
International audience; van der Waals materials offer a large variety of electronic properties depending on chemical composition, number of layers, and stacking order. Among them, As2Te3 has attracted attention due to the promise of outstanding electronic properties, and high photo-response. Precise experimental determinations of the electronic properties of As2Te3 are yet sorely needed for better understanding of potential properties and device applications. Here, we study the structural and electronic properties of α-As2Te3. Scanning transmission electron microscopy coupled to energy X-ray dispersion (STEM-EDX), and micro-Raman spectroscopy all confirm that our specimens correspond to α-As2Te3. Scanning tunneling spectroscopy (STS) at 4.2K demonstrates that α-As2Te3 exhibits an electronic band gap of about 0.4 eV. The material can be exfoliated, revealing the (100) anisotropic surface. Transport measurements on a thick exfoliated sample (bulk-like) confirm the STS results. These findings allows for a deeper understanding of the As2Te3 electronic properties, underlying the potential of V-VI semiconductors for electronic and photonic technologies.
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- 2021
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5. Electronic Structure of Heavy Halogen Atoms Adsorbed on the Cu(111) Surface: A Combined ARPES and First Principles Calculations Study
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Bertrand Kierren, Sarah Xing, Geoffroy Kremer, Julien E. Rault, Giorgio Contini, Yannick Fagot-Revurat, Sébastien Lebègue, Daniel Malterre, Won June Kim, Patrick Le Fèvre, François Bertran, Muriel Sicot, Dario Rocca, Laboratoire de Physique et Chimie Théoriques (LPCT), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Istituto di Struttura della Materia (CNR-ISM), Consiglio Nazionale delle Ricerche [Roma] (CNR), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), IMPACT N4S, and ANR-15-IDEX-0004,LUE,Isite LUE(2015)
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Materials science ,Photoemission spectroscopy ,Angle-resolved photoemission spectroscopy ,02 engineering and technology ,Electronic structure ,010402 general chemistry ,DFT ,01 natural sciences ,Molecular physics ,Overlayer ,Ullmann coupling ,Atom ,Physical and Theoretical Chemistry ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,Cu(111) ,[PHYS]Physics [physics] ,ARPES ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Brillouin zone ,General Energy ,Halogen ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Density functional theory ,Br ,0210 nano-technology - Abstract
International audience; By means of angle-resolved photoemission spectroscopy and density functional theory calculations, we investigate the electronic structure of a Br or I atom overlayer on the Cu(111) surface produced by the well-known Ullmann coupling reaction. We found that the iodine adsorbate induces two spin–orbit split highly dispersive bands, which are well-separated from the bulk Cu 3d bands, whereas the bromine-induced bands are flat and largely hybridized with the copper states. Also, our measured constant energy maps show that the I-induced bands have a parabolic shape in the whole surface Brillouin zone, which is confirmed by our calculations. Overall, the agreement between theory and experiments is excellent, giving new insights into the electronic structure of halogen atoms on noble metals and their possible influence on the molecular electronic structure.
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- 2019
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6. Electronic Band Structure of Ultimately Thin Silicon Oxide on Ru(0001)
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César González, Geoffroy Kremer, Yannick J. Dappe, Daniel Malterre, Johann Coraux, Muriel Sicot, Thomas Pierron, Julien E. Rault, Yannick Fagot-Revurat, Bertrand Kierren, Juan Camilo Alvarez Quiceno, Patrick Le Fèvre, François Bertran, Pascal Pochet, Simone Lisi, Institut Jean Lamour (IJL), Université de Lorraine (UL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratory of Atomistic Simulation (LSIM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (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])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), 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]), Systèmes hybrides de basse dimensionnalité (HYBRID), 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]), Groupe Modélisation et Théorie (GMT), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-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), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Systèmes hybrides de basse dimensionnalité (NEEL - HYBRID), 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universidad Autónoma de Madrid (UAM), C. G. acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities through the project MAT2017-88258-R and the 'Mariá de Maeztu' program for units of excellence in R & D (grant no. MDM-2014-0377)., and ANR-14-OHRI-0004,2DTransformers,Matériaux bidimensionnels à changement de phase(2014)
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Materials science ,Photoemission spectroscopy ,Ultrathin silicon oxide film ,Oxide ,General Physics and Astronomy ,Metal-oxide interface ,FOS: Physical sciences ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,7. Clean energy ,01 natural sciences ,symbols.namesake ,chemistry.chemical_compound ,Condensed Matter::Materials Science ,X-ray photoelectron spectroscopy ,General Materials Science ,Silicon oxide ,Electronic band structure ,Condensed Matter - Materials Science ,Fermi level ,General Engineering ,Monolayer ,Materials Science (cond-mat.mtrl-sci) ,Heterojunction ,021001 nanoscience & nanotechnology ,3. Good health ,0104 chemical sciences ,chemistry ,Chemical physics ,Density functional theory calculations ,symbols ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,0210 nano-technology - Abstract
Silicon oxide can be formed in a crystalline form, when prepared on a metallic substrate. It is a candidate support catalyst and possibly the ultimately-thin version of a dielectric host material for two-dimensional materials (2D) and heterostructures. We determine the atomic structure and chemical bonding of the ultimately thin version of the oxide, epitaxially grown on Ru(0001). In particular, we establish the existence of two sub-lattices defined by metal-oxygen-silicon bridges involving inequivalent substrate sites. We further discover four electronic bands below Fermi level, at high binding energies, two of them forming a Dirac cone at K point, and two others forming semi-flat bands. While the latter two correspond to hybridized states between the oxide and the metal, the former relate to the topmost silicon-oxygen plane, which is not directly coupled to the substrate. Our analysis is based on high resolution X-ray photoelectron spectroscopy, angle-resolved photoemission spectroscopy, scanning tunneling microscopy, and density functional theory calculations., Comment: Main part : 31 pages, 6 figures / Supporting information : 13 pages, 11 figures
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- 2019
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7. Evidence of direct electronic band gap in two-dimensional van der Waals indium selenide crystals
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Federico Bisti, Jihene Zribi, Julien E. Rault, Abhay Shukla, Christine Giorgetti, Debora Pierucci, Julien Chaste, Jean-Christophe Girard, Fausto Sirotti, Abdelkarim Ouerghi, Luca Perfetti, François Bertran, Patrick Le Fèvre, Hugo Henck, Evangelos Papalazarou, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Laboratoire Pierre Aigrain (LPA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), 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), 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), Fédération de recherche du Département de physique de l'Ecole Normale Supérieure - ENS Paris (FRDPENS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Université Paris Diderot - Paris 7 (UPD7)-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), 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), and ANR-17-CE24-0030,RhomboG,Propriétés electroniques de couches minces de graphite rhombohedrique(2017)
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Materials science ,Physics and Astronomy (miscellaneous) ,Photoemission spectroscopy ,Scanning tunneling spectroscopy ,FOS: Physical sciences ,Angle-resolved photoemission spectroscopy ,02 engineering and technology ,Electronic structure ,01 natural sciences ,symbols.namesake ,Effective mass (solid-state physics) ,Condensed Matter::Superconductivity ,Mesoscale and Nanoscale Physics (cond-mat.mes-hall) ,0103 physical sciences ,General Materials Science ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Condensed Matter - Mesoscale and Nanoscale Physics ,Condensed matter physics ,021001 nanoscience & nanotechnology ,Brillouin zone ,[PHYS.COND.CM-GEN]Physics [physics]/Condensed Matter [cond-mat]/Other [cond-mat.other] ,symbols ,Direct and indirect band gaps ,van der Waals force ,0210 nano-technology - Abstract
Metal mono-chalcogenide compounds offer a large variety of electronic properties depending on chemical composition, number of layers and stacking-order. Among them, the InSe has attracted much attention due to the promise of outstanding electronic properties, attractive quantum physics, and high photo-response. Metal mono-chalcogenide compounds offer a large variety of electronic properties depending on chemical composition, number of layers and stacking-order. Among them, the InSe has attracted much attention due to the promise of outstanding electronic properties, attractive quantum physics, and high photo-response. Precise experimental determination of the electronic structure of InSe is sorely needed for better understanding of potential properties and device applications. Here, combining scanning tunneling spectroscopy (STS) and two-photon photoemission spectroscopy (2PPE), we demonstrate that InSe exhibits a direct band gap of about 1.25 eV located at the Gamma point of the Brillouin zone (BZ). STS measurements underline the presence of a finite and almost constant density of states (DOS) near the conduction band minimum (CBM) and a very sharp one near the maximum of the valence band (VMB). This particular DOS is generated by a poorly dispersive nature of the top valence band, as shown by angle resolved photoemission spectroscopy (ARPES) investigation. technologies. In fact, a hole effective mass of about m/m0 = -0.95 gammaK direction) was measured. Moreover, using ARPES measurements a spin-orbit splitting of the deeper-lying bands of about 0.35 eV was evidenced. These findings allow a deeper understanding of the InSe electronic properties underlying the potential of III-VI semiconductors for electronic and photonic
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- 2019
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8. Temperature-driven modification of surface electronic structure on bismuth, a topological border material
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J. Kishi, Kiyohisa Tanaka, Yoshiyuki Ohtsubo, S. Ideta, Julien E. Rault, Yuki Yamashita, Shin-ichi Kimura, François Bertran, Hiroyuki Yamane, and P. Le Fèvre
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Condensed Matter - Materials Science ,Valence (chemistry) ,Materials science ,Acoustics and Ultrasonics ,Condensed matter physics ,chemistry.chemical_element ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Angle-resolved photoemission spectroscopy ,02 engineering and technology ,Electronic structure ,Atmospheric temperature range ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Bismuth ,Brillouin zone ,chemistry ,0103 physical sciences ,Topological order ,010306 general physics ,0210 nano-technology ,Surface states - Abstract
Single crystalline bismuth (Bi) is known to have a peculiar electronic structure which is very close to the topological phase transition. The modification of the surface states of Bi depending on the temperature are revealed by angle-resolved photoelectron spectroscopy (ARPES). At low temperature, the upper branch of the surface state merged to the projected bulk conduction bands around the $\bar{M}$ point of the surface Brillouin zone (SBZ). In contrast, the same branch merged to the projected bulk valence bands at high temperature (400 K). Such behavior could be interpreted as a topological phase transition driven by the temperature, which might be applicable for future spin-thermoelectric devices. We discuss the possible mechanisms to cause such transition, such as the thermal lattice distortion and electron-phonon coupling., 15 pages with 6 figures (single column)
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- 2019
9. Surface Kondo effect and non-trivial metallic state of the Kondo insulator YbB12
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S. Ideta, Fumitoshi Iga, Amina Taleb-Ibrahimi, Koji Horiba, Masaharu Matsunami, Ryu Yukawa, Hidetoshi Miyazaki, Patrick Le Fèvre, Kenta Hagiwara, François Bertran, Julien E. Rault, Hiroshi Kumigashira, Kiyohisa Tanaka, Shin-ichi Kimura, Taichi Okuda, Masaki Kobayashi, Kazuki Sumida, and Yoshiyuki Ohtsubo
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Surface (mathematics) ,Science ,FOS: Physical sciences ,General Physics and Astronomy ,02 engineering and technology ,01 natural sciences ,Article ,General Biochemistry, Genetics and Molecular Biology ,Condensed Matter - Strongly Correlated Electrons ,0103 physical sciences ,Topological order ,010306 general physics ,Quantum ,Surface states ,Physics ,Multidisciplinary ,Strongly Correlated Electrons (cond-mat.str-el) ,Condensed matter physics ,Electronic correlation ,Kondo insulator ,General Chemistry ,021001 nanoscience & nanotechnology ,Brillouin zone ,Condensed Matter::Strongly Correlated Electrons ,Kondo effect ,0210 nano-technology - Abstract
A synergistic effect between strong electron correlation and spin-orbit interaction (SOI) has been theoretically predicted to result in a new topological state of quantum matter on Kondo insulators (KIs), so-called topological Kondo insulators (TKIs). One TKI candidate has been experimentally observed on the KI SmB6(001), and the origin of the surface states (SS) and the topological order of SmB6 has been actively discussed. Here, we show a metallic SS on the clean surface of another TKI candidate YbB12(001), using angle-resolved photoelectron spectroscopy. The SS showed temperature-dependent reconstruction corresponding with the Kondo effect observed for bulk states. Despite the low-temperature insulating bulk, the reconstructed SS with c-f hybridization was metallic, forming a closed Fermi contour surrounding $\bar{\Gamma}$ on the surface Brillouin zone and agreeing with the theoretically expected behavior for SS on TKIs. These results demonstrate the temperature-dependent holistic reconstruction of two-dimensional states localized on KIs surface driven by the Kondo effect., Comment: 15 pages, 4 figures
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- 2016
10. Electronic band structure of Two-Dimensional WS 2 /Graphene van der Waals Heterostructures
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Feriel Laourine, Hugo Henck, Patrick Le Fèvre, François Bertran, Zeineb Ben Aziza, Francesco Reale, Taro Wakamura, Julien E. Rault, Debora Pierucci, Matteo Calandra, Abdelkarim Ouerghi, Julien Chaste, Mathieu G. Silly, Cecilia Mattevi, Emmanuel Lhuillier, Pawel Palczynski, Centre de Nanosciences et de Nanotechnologies [Marcoussis] (C2N), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), ALBA Synchrotron light source [Barcelone], Imperial College London, Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Physico-chimie et dynamique des surfaces (INSP-E6), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Solides (LPS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11), Spectroscopie des nouveaux états quantiques (INSP-E2), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), ANR-15-CE24-0016,H2DH,Hétérostructures bi-dimendionnelles hybrides pour l'optoélectronique(2015), Centre de Nanosciences et Nanotechnologies (C2N (UMR_9001)), Centre de Nanosciences et de Nanotechnologies (C2N), Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Engineering & Physical Science Research Council (EPSRC)
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Electronic structure, Semiconductors ,2-dimensional systems, Transition-metal dichalcogenide ,Photoemission spectroscopy ,Electronic structure ,Van der waals heterostructures ,FOS: Physical sciences ,02 engineering and technology ,01 natural sciences ,law.invention ,Condensed Matter::Materials Science ,law ,0103 physical sciences ,[PHYS.COND]Physics [physics]/Condensed Matter [cond-mat] ,010306 general physics ,Spectroscopy ,Electronic band structure ,[PHYS]Physics [physics] ,Physics ,Condensed Matter - Materials Science ,Condensed matter physics ,Graphene ,2-dimensional systems ,Materials Science (cond-mat.mtrl-sci) ,Heterojunction ,Transition-metal dichalcogenide ,021001 nanoscience & nanotechnology ,Hybrid functional ,Semiconductors ,Density functional theory ,0210 nano-technology - Abstract
Combining single-layer two-dimensional semiconducting transition metal dichalcogenides (TMDs) with graphene layer in van der Waals heterostructures offers an intriguing means of controlling the electronic properties through these heterostructures. Here, we report the electronic and structural properties of transferred single layer WS2 on epitaxial graphene using micro-Raman spectroscopy, angle-resolved photoemission spectroscopy measurements (ARPES) and Density Functional Theory (DFT) calculations. The results show good electronic properties as well as well-defined band arising from the strong splitting of the single layer WS2 valence band at K points, with a maximum splitting of 0.44 eV. By comparing our DFT results with local and hybrid functionals, we find the top valence band of the experimental heterostructure is close to the calculations for suspended single layer WS2. . Our results provide an important reference for future studies of electronic properties of WS2 and its applications in valleytronic devices., Comment: 11 pages, 3 figures + SI 7 pages 8 figures
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- 2018
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11. Characterization of free-standing InAs quantum membranes by standing wave hard x-ray photoemission spectroscopy
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Hui Fang, Osman Karslıoğlu, Mathias Gehlmann, A. Rattanachata, Julien E. Rault, Hendrik Bluhm, J. Mueller, G. Conti, James A. Sethian, Jean-Pascal Rueff, Cheng-Tai Kuo, C. Conlon, A. Keqi, Slavomír Nemšák, Ali Javey, and Charles S. Fadley
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Materials science ,Photoemission spectroscopy ,lcsh:Biotechnology ,Oxide ,02 engineering and technology ,01 natural sciences ,Molecular physics ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,lcsh:TP248.13-248.65 ,0103 physical sciences ,General Materials Science ,Electrical and Electronic Engineering ,Spectroscopy ,010302 applied physics ,business.industry ,Mechanical Engineering ,General Engineering ,Heterojunction ,Materials Engineering ,021001 nanoscience & nanotechnology ,cond-mat.mtrl-sci ,lcsh:QC1-999 ,Chemical state ,Semiconductor ,chemistry ,X-ray crystallography ,0210 nano-technology ,business ,ddc:600 ,lcsh:Physics - Abstract
© 2018 Author(s). Free-standing nanoribbons of InAs quantum membranes (QMs) transferred onto a (Si/Mo) multilayer mirror substrate are characterized by hard x-ray photoemission spectroscopy (HXPS) and by standing-wave HXPS (SW-HXPS). Information on the chemical composition and on the chemical states of the elements within the nanoribbons was obtained by HXPS and on the quantitative depth profiles by SW-HXPS. By comparing the experimental SW-HXPS rocking curves to x-ray optical calculations, the chemical depth profile of the InAs(QM) and its interfaces were quantitatively derived with ångström precision. We determined that (i) the exposure to air induced the formation of an InAsO4 layer on top of the stoichiometric InAs(QM); (ii) the top interface between the air-side InAsO4 and the InAs(QM) is not sharp, indicating that interdiffusion occurs between these two layers; (iii) the bottom interface between the InAs(QM) and the native oxide SiO2 on top of the (Si/Mo) substrate is abrupt. In addition, the valence band offset (VBO) between the InAs(QM) and the SiO2/(Si/Mo) substrate was determined by HXPS. The value of VBO = 0.2 ± 0.04 eV is in good agreement with literature results obtained by electrical characterization, giving a clear indication of the formation of a well-defined and abrupt InAs/SiO2 heterojunction. We have demonstrated that HXPS and SW-HXPS are non-destructive, powerful methods for characterizing interfaces and for providing chemical depth profiles of nanostructures, quantum membranes, and 2D layered materials.
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- 2018
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12. Large area molybdenum disulphide-epitaxial graphene vertical Van der Waals heterostructures
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A. T. Charlie Johnson, Carl H. Naylor, Haikel Sediri, Adrian Balan, Patrick Le Fèvre, Debora Pierucci, Hugo Henck, François Bertran, Abdelkarim Ouerghi, Emmanuel Lhuillier, Yannick J. Dappe, Julien E. Rault, Laboratoire de photonique et de nanostructures (LPN), Centre National de la Recherche Scientifique (CNRS), University of Pennsylvania [Philadelphia], Physico-chimie et dynamique des surfaces (INSP-E6), Institut des Nanosciences de Paris (INSP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Synchrotron SOLEIL (SSOLEIL), 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), University of Pennsylvania, Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Angle-resolved photoemission spectroscopy ,02 engineering and technology ,Substrate (electronics) ,01 natural sciences ,Article ,law.invention ,[SPI.MAT]Engineering Sciences [physics]/Materials ,chemistry.chemical_compound ,symbols.namesake ,law ,0103 physical sciences ,Monolayer ,010306 general physics ,Molybdenum disulfide ,Multidisciplinary ,business.industry ,Graphene ,Heterojunction ,[CHIM.MATE]Chemical Sciences/Material chemistry ,021001 nanoscience & nanotechnology ,chemistry ,symbols ,[PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci] ,Optoelectronics ,Direct and indirect band gaps ,van der Waals force ,0210 nano-technology ,business - Abstract
Two-dimensional layered transition metal dichalcogenides (TMDCs) show great potential for optoelectronic devices due to their electronic and optical properties. A metal-semiconductor interface, as epitaxial graphene - molybdenum disulfide (MoS2), is of great interest from the standpoint of fundamental science, as it constitutes an outstanding platform to investigate the interlayer interaction in van der Waals heterostructures. Here, we study large area MoS2-graphene-heterostructures formed by direct transfer of chemical-vapor deposited MoS2 layer onto epitaxial graphene/SiC. We show that via a direct transfer, which minimizes interface contamination, we can obtain high quality and homogeneous van der Waals heterostructures. Angle-resolved photoemission spectroscopy (ARPES) measurements combined with Density Functional Theory (DFT) calculations show that the transition from indirect to direct bandgap in monolayer MoS2 is maintained in these heterostructures due to the weak van der Waals interaction with epitaxial graphene. A downshift of the Raman 2D band of the graphene, an up shift of the A1g peak of MoS2 and a significant photoluminescence quenching are observed for both monolayer and bilayer MoS2 as a result of charge transfer from MoS2 to epitaxial graphene under illumination. Our work provides a possible route to modify the thin film TDMCs photoluminescence properties via substrate engineering for future device design.
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- 2016
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13. Observation by resonant angle-resolved photoemission of a critical thickness for 2-dimensional electron gas formation in SrTiO$_3$ embedded in GdTiO$_3$
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Slavomír Nemšák, Julien E. Rault, Pouya Moetakef, S. Cho, G. Conti, Clayton A. Jackson, Susanne Stemmer, C. G. Van de Walle, Burak Himmetoglu, Charles S. Fadley, C. Conlon, Gunnar K. Pálsson, Maria C. Asensio, Anderson Janotti, Claus M. Schneider, José Avila, Lars Bjaalie, and Leon Balents
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Condensed Matter - Materials Science ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Strongly Correlated Electrons (cond-mat.str-el) ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Layer thickness ,Spectral line ,Condensed Matter - Strongly Correlated Electrons ,Ferromagnetism ,ddc:530 ,Fermi gas ,Critical thickness ,Layer (electronics) - Abstract
For certain conditions of layer thickness, the interface between GdTiO$_3$ (GTO) and SrTiO$_3$ (STO) in multilayer samples has been found to form a two-dimensional electron gas (2DEG) with very interesting properties including high mobilities and ferromagnetism. We have here studied two trilayer samples of the form [2 nm GTO/1.0 or 1.5 unit cells STO/10 nm GTO] as grown on (001) (LaAlO$_3$)$_{0.3}$(Sr$_2$AlTaO$_6$)$_{0.7}$ (LSAT), with the STO layer thicknesses being at what has been suggested is the critical thickness for 2DEG formation. We have studied these with Ti-resonant angle-resolved (ARPES) and angle-integrated photoemission and find that the spectral feature in the spectra associated with the 2DEG is present in the 1.5 unit cell sample, but not in the 1.0 unit cell sample. We also observe through core-level spectra additional states in Ti and Sr, with the strength of a low-binding-energy state for Sr being associated with the appearance of the 2DEG, and we suggest it to have an origin in final-state core-hole screening., 12 pages, 4 figures
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- 2015
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14. Narrow-band Anisotropic Electronic Structure of ReS2
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Worawat Meevasana, Deepnarayan Biswas, Phil D. C. King, Alex M. Ganose, O. J. Clark, R. Yano, Julien E. Rault, Timur K. Kim, Moritz Hoesch, David O. Scanlon, J. M. Riley, L. Collins-Mcintyre, Jiagui Feng, M. T. Sajjad, L. Bawden, Takao Sasagawa, EPSRC, The Royal Society, University of St Andrews. School of Physics and Astronomy, University of St Andrews. University of St Andrews, and University of St Andrews. Condensed Matter Physics
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Physics ,Condensed Matter - Materials Science ,Valence (chemistry) ,Condensed matter physics ,Photoemission spectroscopy ,Band gap ,TK ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,DAS ,02 engineering and technology ,Electronic structure ,021001 nanoscience & nanotechnology ,01 natural sciences ,TK Electrical engineering. Electronics Nuclear engineering ,Brillouin zone ,QC Physics ,Zigzag ,0103 physical sciences ,Condensed Matter::Strongly Correlated Electrons ,010306 general physics ,0210 nano-technology ,Electronic band structure ,Anisotropy ,QC - Abstract
We have used angle-resolved photoemission spectroscopy to investigate the band structure of ${\mathrm{ReS}}_{2}$, a transition-metal dichalcogenide semiconductor with a distorted 1T crystal structure. We find a large number of narrow valence bands, which we attribute to the combined influence of structural distortion and spin-orbit coupling. We further show how this leads to a strong in-plane anisotropy of the electronic structure, with quasi-one-dimensional bands reflecting predominant hopping along zigzag Re chains. We find that this does not persist up to the top of the valence band, where a more three-dimensional character is recovered with the fundamental band gap located away from the Brillouin zone center along ${k}_{z}$. These experiments are in good agreement with our density-functional theory calculations, shedding light on the bulk electronic structure of ${\mathrm{ReS}}_{2}$, and how it can be expected to evolve when thinned to a single layer.
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- 2017
15. Charge spill-out and work function of few-layer graphene on SiC(0 0 0 1)
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Claire Mathieu, O. Renault, K. Kaja, A. M. Pascon, T. Poiroux, H. Rotella, P. Blaise, Leonardo R. C. Fonseca, Julien E. Rault, Nicholas Barrett, 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), University of Campinas [Campinas] (UNICAMP), Laboratoire de cristallographie et sciences des matériaux (CRISMAT), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC), Institut de Droit Européen des Droits de l'Homme - EA 3976 (IDEDH), Université de Montpellier (UM), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Laboratoire de Simulation et Modélisation (LSM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de statistiques et modélisation (LSM), Centre de Recherche en Économie et STatistique (CREST), Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Universidade Estadual de Campinas = University of Campinas (UNICAMP), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)
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Materials science ,Acoustics and Ultrasonics ,Binding energy ,Ab initio simulation ,Ab initio ,FOS: Physical sciences ,Silicon carbide ,02 engineering and technology ,Electron ,Epitaxy ,Work function ,01 natural sciences ,law.invention ,law ,0103 physical sciences ,Physics::Atomic and Molecular Clusters ,010306 general physics ,[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,Condensed matter physics ,Graphene ,XPEEM ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Dipole ,Density functional theory ,0210 nano-technology - Abstract
We report on the charge spill-out and work function of epitaxial few-layer graphene on 6H-SiC(0001). Experiments from high-resolution, energy-filtered X-ray photoelectron emission microscopy (XPEEM) are combined with ab initio Density Functional Theory calculations using a relaxed interface model. Work function values obtained from theory and experiments are in qualitative agreement, reproducing the previously observed trend of increasing work function with each additional graphene plane. Electrons transfer at the SiC/graphene interface through a buffer layer causes an interface dipole moment which is at the origin of the graphene work function modulation. The total charge transfer is independent of the number of graphene layers, and is consistent with the constant binding energy of the SiC component of the C 1s core-level measured by XPEEM. Charge leakage into vacuum depends on the number of graphene layers explaining why the experimental, layer-dependent C 1s-graphene core-level binding energy shift does not rigidly follow that of the work function. Thus, a combination of charge transfer at the SiC/graphene interface and charge spill-out into vacuum resolves the apparent discrepancy between the experimental work function and C1s binding energy., 14 pages, 9 figures
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- 2014
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16. Polarization Sensitive Surface Band Structure of Doped BaTiO_{3}(001)
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Julien E. Rault, Christian Schneider, Grégory Geneste, Vitaliy Feyer, C. Mathieu, Nicholas Barrett, and J. Dionot
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Condensed Matter - Materials Science ,Materials science ,Condensed matter physics ,business.industry ,Doping ,General Physics and Astronomy ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,02 engineering and technology ,Electronic structure ,021001 nanoscience & nanotechnology ,Polarization (waves) ,01 natural sciences ,Ferroelectricity ,Spectral line ,Reciprocal lattice ,Condensed Matter::Materials Science ,Optics ,0103 physical sciences ,ddc:550 ,010306 general physics ,0210 nano-technology ,business ,Electronic band structure ,Single crystal - Abstract
We present a spatial and wave-vector resolved study of the electronic structure of micron sized ferroelectric domains at the surface of a BaTiO3(001) single crystal. The n-type doping of the BaTiO3 is controlled by in-situ vacuum and oxygen annealing, providing experimental evidence of a surface paraelectric-ferroelectric transition below a critical doping level. Real space imaging of photoemission threshold, core level and valence band spectra show contrast due to domain polarization. Reciprocal space imaging of the electronic structure using linearly polarized light provides unambiguous evidence for the presence of both in and out-of plane polarization with two and fourfold symmetry, respectively. The results agree well with first principles calculations., Comment: 6 pages, 5 figures
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- 2013
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17. Time-resolved photoemission spectroscopy on a metal/ferroelectric heterostructure
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Bertrand Vilquin, Julien E. Rault, Azzedine Bendounan, Thomas Maroutian, Mathieu G. Silly, Fausto Sirotti, Gang Niu, V. Pillard, Nicholas Barrett, Ph. Lecoeur, Guillaume Agnus, Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'électronique fondamentale (IEF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), INL - Hétéroepitaxie et Nanostructures (INL - H&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), ANR-10-BLAN-1012,Surf-FER,Modifications de la structure chimique et électronique de surfaces ferroélectriques sous adsorption de H2O(2010), ANR-07-BLAN-0312,MINOS,Monolithic INtegration of functional Oxides on Silicon for novel micro-system devices(2007), Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), and Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)
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[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,Materials science ,Condensed matter physics ,Photoemission spectroscopy ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Heterojunction ,02 engineering and technology ,Electronic structure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Capacitance ,Ferroelectricity ,Electronic, Optical and Magnetic Materials ,0103 physical sciences ,Electrode ,Transient response ,PACS number(s): 77.80.−e, 73.21.Ac, 73.40.−c, 77.84.−s ,010306 general physics ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
In thin film ferroelectric capacitor the chemical and electronic structure of the electrode/FE interface can play a crucial role in determining the kinetics of polarization switching. We investigate the electronic structure of a Pt/BaTiO3/SrTiO3:Nb capacitor using time-resolved photoemission spectroscopy. The chemical, electronic and depth sensitivity of core level photoemission is used to probe the transient response of different parts of the upper electrode/ferroelectric interface to voltage pulse induced polarization reversal. The linear response of the electronic structure agrees quantitatively with a simple RC circuit model. The non-linear response due to the polarization switch is demonstrated by the time-resolved response of the characteristic core levels of the electrode and the ferroelectric. Adjustment of the RC circuit model allows a first estimation of the Pt/BTO interface capacitance. The experiment shows the interface capacitance is at least 100 times higher than the bulk capacitance of the BTO film, in qualitative agreement with theoretical predictions from the literature., Comment: 7 pages, 10 figures. Submitted to Phys. Rev. B
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- 2013
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18. Full field electron spectromicroscopy applied to ferroelectric materials
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Julien E. Rault, Wei Ren, Alain Barthélémy, Andrea Locatelli, Junling Wang, I. P. Krug, Miguel Angel Niño, Sergey Prosandeev, Christian Schneider, Nicholas Barrett, Tevfik Onur Menteş, A. Petraru, Laurent Bellaiche, Bertrand Vilquin, Claire Mathieu, Daniel Sando, Stéphane Fusil, Manuel Bibes, Laboratoire d'Etude des NanoStructures et Imagerie de Surface (LENSIS), 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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts (CHNO), TEDA School of Biological Sciences and Biotechnology, Nankai University (NKU), Key Laboratory of Molecular Microbiology and Technology, ministry of education, Faculté de sciences Economiques et de Gestion, Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Elettra Sincrotrone Trieste, Laboratorio de Electrofisiologia (LEFS), Universidad Nacional de Colombia, Unité mixte de physique CNRS/Thales (UMPhy CNRS/THALES), THALES [France]-Centre National de la Recherche Scientifique (CNRS), Photonique Fibre et Sources Cohérentes (XLIM-PHOT), XLIM (XLIM), Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS)-Université de Limoges (UNILIM)-Centre National de la Recherche Scientifique (CNRS), China Information Technology Security Evaluation Center (CNITSEC), Department of Physics Department [Fayetteville], University of Arkansas [Fayetteville], Institute for nanosciences and engineering and physics departement [University of Arkansas], Department Physics, Université de Lyon, INL - Hétéroepitaxie et Nanostructures (INL - H&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), THALES-Centre National de la Recherche Scientifique (CNRS), China Information Technology Security Evaluation Center, and Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon)
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Materials science ,General Physics and Astronomy ,FOS: Physical sciences ,02 engineering and technology ,Electron ,01 natural sciences ,Condensed Matter::Materials Science ,0103 physical sciences ,Work function ,ddc:530 ,010306 general physics ,Electronic band structure ,[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,business.industry ,Materials Science (cond-mat.mtrl-sci) ,021001 nanoscience & nanotechnology ,Ferroelectricity ,3. Good health ,Photoemission electron microscopy ,Reciprocal lattice ,Low-energy electron microscopy ,Electron optics ,Optoelectronics ,0210 nano-technology ,business - Abstract
The application of PhotoEmission Electron Microscopy (PEEM) and Low Energy Electron Microscopy (LEEM) techniques to the study of the electronic and chemical structure of ferroelectric materials is reviewed. Electron optics in both techniques gives spatial resolution of a few tens of nanometres. PEEM images photoelectrons whereas LEEM images reflected and elastically backscattered electrons. Both PEEM and LEEM can be used in direct and reciprocal space imaging. Together, they provide access to surface charge, work function, topography, chemical mapping, surface crystallinity and band structure. Examples of applications for the study of ferroelectric thin films and single crystals are presented., Comment: 15 pages, 9 figures
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- 2013
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19. Interface electronic structure in a metal/ferroelectric heterostructure under applied bias
- Author
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Guillaume Agnus, V. Pillard, Julien E. Rault, Fausto Sirotti, Azzedine Bendounan, Mathieu G. Silly, Nicholas Barrett, Thomas Maroutian, Gang Niu, Bertrand Vilquin, Ph. Lecoeur, Service de Physique et de Chimie des Surfaces et Interfaces (SPCSI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut d'électronique fondamentale (IEF), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), INL - Hétéroepitaxie et Nanostructures (INL - H&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), ANR-10-BLAN-1012,Surf-FER,Modifications de la structure chimique et électronique de surfaces ferroélectriques sous adsorption de H2O(2010), ANR-07-BLAN-0312,MINOS,Monolithic INtegration of functional Oxides on Silicon for novel micro-system devices(2007), Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Université de Lyon-Institut National des Sciences Appliquées (INSA)-École Centrale de Lyon (ECL), Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE), and Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon)
- Subjects
[PHYS]Physics [physics] ,Condensed Matter - Materials Science ,Condensed matter physics ,Materials Science (cond-mat.mtrl-sci) ,FOS: Physical sciences ,Biasing ,Heterojunction ,02 engineering and technology ,Electronic structure ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Ferroelectricity ,Electronic, Optical and Magnetic Materials ,Core (optical fiber) ,Condensed Matter::Materials Science ,X-ray photoelectron spectroscopy ,0103 physical sciences ,Electrode ,PACS number(s): 77.80.−e, 73.21.Ac, 73.40.−c, 77.84.−s ,010306 general physics ,0210 nano-technology ,Polarization (electrochemistry) - Abstract
The effective barrier height between an electrode and a ferroelectric (FE) depends on both macroscopic electrical properties and microscopic chemical and electronic structure. The behavior of a prototypical electrode/FE/electrode structure, Pt/BaTiO3/Nb-doped SrTiO3, under in-situ bias voltage is investigated using X-Ray Photoelectron Spectroscopy. The full band alignment is measured and is supported by transport measurements. Barrier heights depend on interface chemistry and on the FE polarization. A differential response of the core levels to applied bias as a function of the polarization state is observed, consistent with Callen charge variations near the interface., Comment: 9 pages, 8 figures. Submitted to Phys. Rev. B
- Published
- 2013
- Full Text
- View/download PDF
20. Depth Profiling Charge Accumulation from a Ferroelectricinto a Doped Mott Insulator.
- Author
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Maya Marinova, Julien E. Rault, Alexandre Gloter, Slavomir Nemsak, Gunnar K. Palsson, Jean-Pascal Rueff, CharlesS. Fadley, Cécile Carrétéro, Hiroyuki Yamada, Katia March, Vincent Garcia, Stéphane Fusil, Agnès Barthélémy, Odile Stéphan, Christian Colliex, and Manuel Bibes
- Subjects
- *
DEPTH profiling , *FERROELECTRIC crystals , *MOTT effect (Physics) , *ELECTRIC insulators & insulation , *STORAGE batteries , *ELECTRIC fields , *CHARGE density waves - Abstract
Theelectric field control of functional properties is a crucial goalin oxide-based electronics. Nonvolatile switching between differentresistivity or magnetic states in an oxide channel can be achievedthrough charge accumulation or depletion from an adjacent ferroelectric.However, the way in which charge distributes near the interface betweenthe ferroelectric and the oxide remains poorly known, which limitsour understanding of such switching effects. Here, we use a first-of-a-kindcombination of scanning transmission electron microscopy with electronenergy loss spectroscopy, near-total-reflection hard X-ray photoemissionspectroscopy, and ab initio theory to address this issue. We achievea direct, quantitative, atomic-scale characterization of the polarization-inducedcharge density changes at the interface between the ferroelectricBiFeO3and the doped Mott insulator Ca1–xCexMnO3, thusproviding insight on how interface-engineering can enhance these switchingeffects. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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