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115 results on '"Fouchet, Arnaud"'

3. Tuning the metal-insulator transition in epitaxial SrVO3 films by uniaxial strain

Author

Wang, Changan, Zhang, Hongbin, Deepak, Kumar, Chen, 5Chao, Fouchet, Arnaud, Duan, Juanmei, Hilliard, Donovan, Kentsch, Ulrich, Chen, Deyang, Zeng, Min, Gao, Xingsen, Zeng, Yu-Jia, Helm, Manfred, Prellier, Wilfrid, and Zhou, Shengqiang

Subjects
Condensed Matter - Materials Science
Abstract

Understanding of the metal-insulator transition (MIT) in correlated transition-metal oxides is a fascinating topic in condensed matter physics and a precise control of such transitions plays a key role in developing novel electronic devices. Here we report an effective tuning of the MIT in epitaxial SrVO3 (SVO) films by expanding the out-of-plane lattice constant without changing in-plane lattice parameters, through helium ion irradiation. Upon increase of the ion fluence, we observe a MIT with a crossover from metallic to insulating state in SVO films. A combination of transport and magnetoresistance measurements in SVO at low temperatures reveals that the observed MIT is mainly ascribed to electron-electron interactions rather than disorder-induced localization. Moreover, these results are well supported by the combination of density functional theory and dynamical mean field theory (DFT+DMFT) calculations, further confirming the decrease of the bandwidth and the enhanced electron-electron interactions resulting from the expansion of out-of-plane lattice constant. These findings provide new insights into the understanding of MIT in correlated oxides and perspectives for the design of unexpected functional devices based on strongly correlated electrons., Comment: 17 pages, 4 figures,submitted to Phys. Rev. Materials

Published
2019
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4. Magnetism tailored by mechanical strain engineering in PrVO$_3$ thin films

Author

Kumar, Deepak, David, Adrian, Fouchet, Arnaud, Pautrat, Alain, Varignon, Julien, Jung, Chang Uk, Lüders, Ulrike, Domengès, Bernadette, Copie, Olivier, Ghosez, Philippe, and Prellier, Wilfrid

Subjects
Condensed Matter - Materials Science
Abstract

Transition-metal oxides with an ABO$_3$ perovskite structure exhibit strongly entangled structural and electronic degrees of freedom and thus, one expects to unveil exotic phases and properties by acting on the lattice through various external stimuli. Using the Jahn-Teller active praseodymium vanadate Pr$^{3+}$V$^{3+}$O$_3$ compound as a model system, we show that PrVO$_3$ N\'eel temperature T$_N$ can be raised by 40 K with respect to the bulk when grown as thin films. Using advanced experimental techniques, this enhancement is unambiguously ascribed to a tetragonality resulting from the epitaxial compressive strain experienced by the films. First-principles simulations not only confirm experimental results, but they also reveal that the strain promotes an unprecedented orbital-ordering of the V$^{3+}$ d electrons, strongly favouring antiferromagnetic interactions. These results show that an accurate control of structural aspects is the key for unveiling unexpected phases in oxides.

Published
2019
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6. Structural, optical, and electrical properties of TiO2 thin films deposited by ALD: Impact of the substrate, the deposited thickness and the deposition temperature

Author

Jolivet, Aline, Labbé, Christophe, Frilay, Cédric, Debieu, Olivier, Marie, Philippe, Horcholle, Bryan, Lemarié, Franck, Portier, Xavier, Grygiel, Clara, Duprey, Sylvain, Jadwisienczak, Wojciech, Ingram, David, Upadhyay, Mudit, David, Adrian, Fouchet, Arnaud, Lüders, Ulrike, and Cardin, Julien

Published
2023
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7. Interface chemical and electronic properties of LaAlO3/SrVO3 heterostructures

Author

Fouchet, Arnaud, Rault, Julien E., Allain, Mickaël, Bérini, Bruno, Rueff, J. -P., Dumont, Yves, and Keller, Niels

Subjects
Condensed Matter - Materials Science
Abstract

We have studied the chemical and electronic properties of LaAlO3/SrVO3 ultrathin films by combining hard x-ray photoemission spectroscopy and transport measurements. We compare single SrVO3 (SVO) ultrathin films and SrVO3 buried below a polar LaAlO3 (LAO) thin layer, both epitaxially grown on SrTiO3. While ultrathin films (4 unit cells) of SVO do show insulating behavior over the entire temperature range, the LAO/SVO interface has a resistivity minimum at 250 K. When increasing the SVO layer thickness, the minimum is observed to shift to higher temperatures, but the resistivity stays always smaller than that of comparable SVO single films. Hard x-ray photoemission spectroscopy reveals a surface or interface related V5+ component in the V 2p spectra for SVO films and LAO/SVO heterostructures, respectively, attributed to a strongly oxidized component. This chemical reconstruction is weaker in LAO/SVO heterostructures compared to single SVO films. We show that this dead layer in SVO ultrathin films has to be considered when the film thickness reaches the few unit-cells limit and propose solutions on how to prevent this detrimental effect., Comment: 15 pages, 4 figures + SI 2 pages, 1 figure

Published
2018
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8. Tuning the Electronic Properties of LAO/STO Interfaces by Irradiating LAO Surface with Low-Energy Cluster Ion Beams

Author

Ridier, Karl, Aureau, Damien, Bérini, Bruno, Dumont, Yves, Keller, Niels, Vigneron, Jackie, Etcheberry, Arnaud, and Fouchet, Arnaud

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We have investigated the effects of low-energy ion beam irradiations using argon clusters on the chemical and electronic properties of LaAlO3/SrTiO3 (LAO/STO) heterointerfaces by combining X-ray photoelectron spectroscopy (XPS) and electrical transport measurements. Due to its unique features, we show that a short-time cluster ion irradiation of the LAO surface induces indirect modifications in the chemical properties of the buried STO substrate, with (1) a lowering of Ti atoms oxidation states (from Ti4+ to Ti3+ and Ti2+) correlated to the formation of oxygen vacancies at the LAO surface and (2) the creation of new surface states for Sr atoms. Contrary to what is observed by using higher energy ion beam techniques, this leads to an increase of the electrical conductivity at the LAO/STO interface. Our XPS data clearly reveal the existence of dynamical processes on the titanium and strontium atoms, which compete with the effect of the cluster ion beam irradiation. These relaxation effects are in part attributed to the diffusion of the ion-induced oxygen vacancies in the entire heterostructure, since an increase of the interfacial metallicity is also evidenced far from the irradiated area. These results demonstrate that a local perturbation of the LAO surface can induce new properties at the interface and in the entire heterostructure. This study highlights the possibility of tuning the electronic properties of LAO/STO interfaces by surface engineering, confirming experimentally the intimate connection between LAO surface chemistry and electronic properties of LAO/STO interfaces., Comment: 23 pages, 5 figures

Published
2017
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13. Tuning the Transparency Window of SrVO3Transparent Conducting Oxide

Author

Cheikh, Aïmane, El khaloufi, Oualyd, Rath, Martando, Lüders, Ulrike, Fouchet, Arnaud, Cardin, Julien, Labbé, Christophe, Prellier, Wilfrid, and David, Adrian

Abstract

Correlated transparent conducting oxides (TCOs) have gained great attention, because of their unique combination of transparency and metallic character. SrVO3(SVO) was identified as a high-performance TCO in the visible range. Few studies have investigated band structure engineering through chemical doping to enhance the optical properties of SVO. Here, we use two different strategies by exploiting the band-filling and width of the bands derived from Vanadium to tune the screened plasma frequency ωp*and the interband transition Ep–denergy, corresponding to the optical transparency window edges. For control of the band-filling strategy, it is found that Titanium doped SVO has a wide transparency window, but such a composition does not maintain the high electrical conductivity required for TCO applications. Concerning the bandwidth strategy, the doping of SrVO3by Calcium shows that ωp*remains located in the IR range (1.12 eV), while Ep–dis blue-shifted into the UV region (3.43 eV) due to reinforced electronic correlations. By an appropriate choice of dopant, we successfully increased the size of the transparency window by around 11% from 1.94 eV (SVO) to 2.30 eV (Calcium-doped SVO), while retaining high conductivity of around 2.30 × 104(S·cm–1) and high charge carrier density of 2.93 × 1022cm–3.

Published
2024
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15. Formation and Etching of the Insulating Sr‐Rich V 5+ Phase at the Metallic SrVO 3 Surface Revealed by Operando XAS Spectroscopy Characterizations

Author

Polewczyk, Vincent, primary, Mezhoud, Moussa, additional, Rath, Martando, additional, El‐Khaloufi, Oualyd, additional, Bassato, Ferdinando, additional, Fouchet, Arnaud, additional, Prellier, Wilfrid, additional, Frégnaux, Mathieu, additional, Aureau, Damien, additional, Braglia, Luca, additional, Vinai, Giovanni, additional, Torelli, Piero, additional, and Lüders, Ulrike, additional

Published
2023
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16. Artificial Aging of Thin Films of the Indium-Free Transparent Conducting Oxide SrVO3

Author

Rath, Martando, primary, Mezhoud, Moussa, additional, El Khaloufi, Oualyd, additional, Lebedev, Oleg, additional, Cardin, Julien, additional, Labbé, Christophe, additional, Gourbilleau, Fabrice, additional, Polewczyk, Vincent, additional, Vinai, Giovanni, additional, Torelli, Piero, additional, Fouchet, Arnaud, additional, David, Adrian, additional, Prellier, Wilfrid, additional, and Lüders, Ulrike, additional

Published
2023
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18. Reduction of Biofilm Formation of Pseudomonas Aeruginosa Bacteria Grown on Cu0.75Ti0.25O2 Films

Author

Abhishek, Y., primary, Pradhan, Soumen, additional, Khokholva, Mariya, additional, El-Khaloufi, Oualyd, additional, Khong, Nicole Zi Jia, additional, Lai, Soak Kuan, additional, Fouchet, Arnaud, additional, David, Adrian, additional, Luders, ulrike, additional, Li, Hoi Yeung, additional, Prellier, Wilfrid, additional, and Ramachandra Rao, M.S., additional

Published
2023
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19. Zirconia surface polymer grafting via dopamine-assisted co-deposition and radical photopolymerization

Author

Dezanet, Clément, primary, Dragoe, Diana, additional, Marie, Philippe, additional, Harfouche, Nesrine, additional, Froissart, Sandrine, additional, Fouchet, Arnaud, additional, Rouden, Jacques, additional, Lecourt, Jérôme, additional, Harnois, Christelle, additional, Thébault, Pascal, additional, Baudoux, Jérôme, additional, and Lepoittevin, Bénédicte, additional

Published
2022
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20. Formation and Etching of the Insulating Sr‐Rich V5+ Phase at the Metallic SrVO3 Surface Revealed by Operando XAS Spectroscopy Characterizations.

Author

Polewczyk, Vincent, Mezhoud, Moussa, Rath, Martando, El‐Khaloufi, Oualyd, Bassato, Ferdinando, Fouchet, Arnaud, Prellier, Wilfrid, Frégnaux, Mathieu, Aureau, Damien, Braglia, Luca, Vinai, Giovanni, Torelli, Piero, and Lüders, Ulrike

Subjects
METALLIC surfaces, ETCHING, THIN films, X-ray absorption, SPECTROMETRY, X-ray absorption near edge structure
Abstract

In the search of low cost and more efficient electronic devices, here the properties of SrVO3 transparent conductor oxide (TCO) thin film are investigated, both visible‐range optically transparent and highly conductive, it stands as a promising candidate to substitute the standard indium‐tin‐oxide (ITO) in applications. Its surface stability under water (both liquid and vapor) and other gaseous atmospheres is especially addressed. Through the use of spectroscopy characterizations, X‐ray photoemission and operando X‐ray absorption measurements, the formation of a thin Sr‐rich V5+ layer located at the surface of the polycrystalline SrVO3 film with aging is observed, and for the first time how it can be removed from the surface by solvating in water atmosphere. The surface recovery is associated to an etching process, here spectroscopically characterized in operando conditions, allowing to follow the stoichiometric modification under reaction. Once exposed in oxygen atmosphere, the Sr‐rich V5+ layer forms again. The findings improve the understanding of aging effects in perovskite oxides, allowing for the development of functionalized films in which it is possible to control or to avoid an insulating surface layer. This constitutes an important step towards the large‐scale use of V‐based TCOs, with possible implementations in oxide‐based electronics. [ABSTRACT FROM AUTHOR]

Published
2023
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23. Tunable magnetic and magnetotransport properties in locally epitaxial La0.67Sr0.33MnO3 thin films on polycrystalline SrTiO3, by control of grain size

Author

Dallocchio, Marie, primary, Boileau, Alexis, additional, Mercey, Bernard, additional, David, Adrian, additional, Lüders, Ulrike, additional, Froissart, Sandrine, additional, Larose, Xavier, additional, Bérini, Bruno, additional, Dumont, Yves, additional, Pautrat, Alain, additional, Prellier, Wilfrid, additional, and Fouchet, Arnaud, additional

Published
2022
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24. Fonctionnalisation de surfaces de zircone par photopolymérisation de monomères zwittérioniques

Author

Dezanet, Clément, Lepoittevin, Bénédicte, Baudoux, Jérôme, Rouden, Jacques, Lecourt, Jérôme, Harnois, Christelle, Fouchet, Arnaud, Froissart, Sandrine, Marie, Philippe, Thebault, Pascal, Laboratoire de chimie moléculaire et thioorganique (LCMT), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Normandie Université (NU)-Université Le Havre Normandie (ULH), Normandie Université (NU)-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)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Le Havre Normandie (ULH), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de cristallographie et sciences des matériaux (CRISMAT), 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), 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), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Nanomatériaux, Ions et Métamatériaux pour la Photonique (NIMPH), Centre de recherche sur les Ions, les MAtériaux et la Photonique (CIMAP - UMR 6252), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Polymères Biopolymères Surfaces (PBS), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-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)-Institut Normand de Chimie Moléculaire Médicinale et Macromoléculaire (INC3M), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), and Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021

25. Highly Transparent and Conductive Indium‐Free Vanadates Crystallized at Reduced Temperature on Glass Using a 2D Transparent Nanosheet Seed Layer

Author

Boileau, Alexis, primary, Hurand, Simon, additional, Baudouin, Florent, additional, Lüders, Ulrike, additional, Dallocchio, Marie, additional, Bérini, Bruno, additional, Cheikh, Aimane, additional, David, Adrian, additional, Paumier, Fabien, additional, Girardeau, Thierry, additional, Marie, Philippe, additional, Labbé, Christophe, additional, Cardin, Julien, additional, Aureau, Damien, additional, Frégnaux, Mathieu, additional, Guilloux‐Viry, Maryline, additional, Prellier, Wilfrid, additional, Dumont, Yves, additional, Demange, Valérie, additional, and Fouchet, Arnaud, additional

Published
2021
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27. Spontaneous ordering, strain control, and multifunctionality in vertical nanocomposite heteroepitaxial films

Author

Fouchet, Arnaud, Haiyan Wang, Hao Yang, Jongsik Yoon, Quanxi Jia, and MacManus-Driscoll, Judith Louise

Subjects
Barium compounds -- Electric properties, Barium compounds -- Structure, Magnesium oxide -- Electric properties, Samarium -- Electric properties, Samarium -- Mechanical properties, Titanium -- Electric properties, Titanium -- Mechanical properties, Zirconium -- Electric properties, Business, Electronics, Electronics and electrical industries
Abstract

The strain coupling, microstructural evolution, and functional properties of a series of BaTi[O.sub.3] (BTO) films with different second-phase oxide additions, Ti[O.sub.2], MgO, Zr[O.sub.2], [Sm.sub.2][O.sub.3] and [Y.sub.2][O.sub.3] (YO), is studied. The studies have shown that the strain state in BTO is tuned by different additions and compared with BFO, which is switched from tensile for a pure film on STO to compressive by the presence of the second phase (SmO).

Published
2009

28. Impact of the Growth Mechanisms on Si and Glass Substrates on the Structural, Optical and Electrical Properties of Anatase TiO2 Thin Films Synthetized By ALD Technique (Oral)

Author

Jolivet, Aline, primary, Labbé, Christophe, additional, Frilay, Cédric, additional, Debieu, Olivier, additional, Marie, Philippe, additional, Lemarié, Franck, additional, Portier, Xavier, additional, Grygiel, Clara, additional, Upadhyay, Mudit, additional, David, Adrian, additional, Fouchet, Arnaud, additional, Lüders, Ulrike, additional, and Cardin, Julien, additional

Published
2021
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29. Dopant activity for highly in-situ doped polycrystalline silicon: hall, XRD, scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM)

Author

Coq Germanicus, Rosine, primary, Lallemand, Florent, additional, Chateigner, Daniel, additional, Jouha, Wadia, additional, Moultif, Niemat, additional, Latry, Olivier, additional, Fouchet, Arnaud, additional, Murray, Hugues, additional, Bunel, Catherine, additional, and Lüders, Ulrike, additional

Published
2021
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33. Three dimensional resistance mapping of self-organized Sr3V2O8 nanorods on metallic perovskite SrVO3 matrix

Author

Germanicus, Rosine Coq, primary, Bourlier, Yoan, additional, Notot, Vincent, additional, Bérini, Bruno, additional, Demange, Valérie, additional, Berthe, Maxime, additional, Boileau, Alexis, additional, Euchin, Matthieu, additional, Dumont, Yves, additional, Aureau, Damien, additional, Fregnaux, Mathieu, additional, Grandidier, Bruno, additional, Lüders, Ulrike, additional, David, Adrian, additional, Prellier, Wilfrid, additional, Biadala, Louis, additional, and Fouchet, Arnaud, additional

Published
2020
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35. Highly Transparent and Conductive Indium‐Free Vanadates Crystallized at Reduced Temperature on Glass Using a 2D Transparent Nanosheet Seed Layer.

Author

Boileau, Alexis, Hurand, Simon, Baudouin, Florent, Lüders, Ulrike, Dallocchio, Marie, Bérini, Bruno, Cheikh, Aimane, David, Adrian, Paumier, Fabien, Girardeau, Thierry, Marie, Philippe, Labbé, Christophe, Cardin, Julien, Aureau, Damien, Frégnaux, Mathieu, Guilloux‐Viry, Maryline, Prellier, Wilfrid, Dumont, Yves, Demange, Valérie, and Fouchet, Arnaud

Subjects
VANADATES, GLASS, ELLIPSOMETRY, SEEDS, INDIUM, TEMPERATURE, TRANSPARENT ceramics
Abstract

Indium‐tin‐oxide (ITO) is a widely employed transparent conducting oxide (TCO), but the indium scarcity and price encourage developing some alternatives. The correlated metals CaVO3 and SrVO3 have been recently identified as new TCOs with functional properties being comparable to ITO. However, their technological potential is limited by the critical requirement of a perovskite structure of the film, impossible to achieve via direct growth on substrates commonly used for applications. In this article, the authors tackle this limitation by demonstrating the crystalline growth of vanadate TCOs on glass at temperatures below 600 °C, with the help of 2D nanosheets as transparent seed layers. The functional properties do not suffer from the textured structure of the films, as confirmed by an in‐depth spectroscopic ellipsometry study, allowing for an industrially viable approach to integrate vanadate TCOs on virtually any surface and to exploit their promising performances as a new generation TCO. [ABSTRACT FROM AUTHOR]

Published
2022
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36. Metastable monoclinic [110] layered perovskite Dy2Ti2O7 thin films for ferroelectric applications

Author

Pravarthana, Dhanapal, Lebedev, Oleg I., David, Adrian, Fouchet, Arnaud, Trassin, Morgan, Rohrer, Gregory S., Salvador, Paul A., and Prellier, Wilfrid

Abstract

Using the Combinatorial Substrate Epitaxy (CSE) approach, we report the stabilization of Dy2Ti2O7 epitaxial monoclinic, layered-perovskite phase Dy2Ti2O7 thin films. To achieve this, the films are deposited on high density, polished La2Ti2O7 polycrystalline ceramic substrates, which are stable as monoclinic layered-perovskites, and were prepared by conventional sintering. Microstructural analysis using electron backscatter diffraction (EBSD), electron diffraction (ED), and high-resolution transmission electron microscopy (HRTEM) support this observation. Further, they reveal that the cubic pyrochlore phase is observed far from the interface as films are grown thicker (100 nm), confirming the importance of substrate-induced phase and space group selection. This works reinforces the vast potential of CSE to promote the stabilization of metastable phases, thus giving access to new functional oxide materials, across a range of novel material systems including ferroelectrics., RSC Advances, 9 (35), ISSN:2046-2069

Published
2019
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37. Tuning the electronic properties of LaAlO 3 / SrTiO 3 interfaces by irradiating the LaAlO 3 surface with low-energy cluster ion beams

Author

Ridier, Karl, Aureau, Damien, Berini, Bruno, Dumont, Yves, Keller, Niels, Vigneron, Jackie, Etcheberry, Arnaud, Domengès, Bernadette, Fouchet, Arnaud, Groupe d'Etude de la Matière Condensée (GEMAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), 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), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), and NXP Semiconductors

Subjects
[PHYS]Physics [physics], Electronic structure, X-ray photoelectron spectroscopy, Surface & interfacial phenomena, Electrical conductivity, Oxides, Irradiation effects, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat]
Abstract

International audience; We have investigated the effects of low-energy ion beam irradiations using argon clusters on the chemical and electronic properties of LaAlO3/SrTiO3 (LAO/STO) heterointerfaces by combining x-ray photoelectron spectroscopy (XPS) and electrical transport measurements. Due to its unique features, we demonstrate that a short-time cluster ion irradiation of the LAO surface induces significant modifications in the chemical properties of the buried STO substrate with (1) a lowering of Ti atoms oxidation states (from Ti4+ to Ti3+ and Ti2+) correlated to the formation of oxygen vacancies at the LAO surface and (2) the creation of new surface states for Sr atoms. Contrary to what is generally observed by using higher energy ion beam techniques, this leads to an increase of the electrical conductivity at the LAO/STO interface. Our XPS data clearly reveal the existence of dynamical processes on the titanium and strontium atoms, which compete with the effect of the cluster ion beam irradiation. These relaxation effects are in part attributed to the diffusion of the ion-induced oxygen vacancies in the entire heterostructure since an increase of the interfacial metallicity is also evidenced far from the irradiated area. This paper highlights the possibility of tuning the electrical properties of LAO/STO interfaces by surface engineering, confirming experimentally the intimate connection between LAO chemistry and electronic properties of LAO/STO interfaces.

Published
2018

38. Tuning the metal-insulator transition in epitaxial SrVO3 films by uniaxial strain

Author

Wang, Changan, primary, Zhang, Hongbin, additional, Deepak, Kumar, additional, Chen, Chao, additional, Fouchet, Arnaud, additional, Duan, Juanmei, additional, Hilliard, Donovan, additional, Kentsch, Ulrich, additional, Chen, Deyang, additional, Zeng, Min, additional, Gao, Xingsen, additional, Zeng, Yu-Jia, additional, Helm, Manfred, additional, Prellier, Wilfrid, additional, and Zhou, Shengqiang, additional

Published
2019
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39. Textured Manganite Films Anywhere

Author

Boileau, Alexis, primary, Dallocchio, Marie, additional, Baudouin, Florent, additional, David, Adrian, additional, Lüders, Ulrike, additional, Mercey, Bernard, additional, Pautrat, Alain, additional, Demange, Valérie, additional, Guilloux-Viry, Maryline, additional, Prellier, Wilfrid, additional, and Fouchet, Arnaud, additional

Published
2019
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47. Strontium titanate (100) surfaces monitoring by high temperature in situ ellipsometry

Author

Allain, Mickaël, Janolin, Pierre-Eymeric, Guiblin, Nicolas, Chikoidze, Ekaterina, Scola, Joseph, Popova, Elena, Deb, Marwan, Bocher, Laura, Gloter, Alexandre, Stephan, Odile, Warot-Fonrose, Bénédicte, Hrabovsky, David, Berini, Bruno, Fouchet, Arnaud, Aureau, D., Keller, Niels, Etcheberry, A., Dumont, Yves, Groupe d'Etude de la Matière Condensée (GEMAC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Structures, Propriétés et Modélisation des solides (SPMS), Institut de Chimie du CNRS (INC)-CentraleSupélec-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), 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), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), 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
Materials science, Analytical chemistry, General Physics and Astronomy, 02 engineering and technology, Epitaxy, 01 natural sciences, Overlayer, Atomic layer deposition, chemistry.chemical_compound, X-ray photoelectron spectroscopy, Ellipsometry, 0103 physical sciences, Thin film, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS, 010302 applied physics, Surfaces and Interfaces, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Surfaces, Coatings and Films, chemistry, 13. Climate action, Strontium titanate, 0210 nano-technology, Layer (electronics)
Abstract

We report monitoring and analysis of the contamination overlayer on the surface of different SrTiO3 (STO) substrates by in situ spectroscopic ellipsometry (SE) and ex situ X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). Substrates of STO with different terminations, random and TiO2 terminated, were heated from room temperature up to 720 °C under oxygen pressure in UHV chamber similar to conditions commonly used for epitaxial growth of perovskite oxides. Contamination layer on the substrate was modeled as an equivalent dielectric overlayer with a thickness of 2 nm at room temperature which decreases progressively during the heating up to reach its minimum (around 1 unit cell) at the temperature around 550 °C. After exposition to air, surface recovers a contamination layer on both types of substrates (with random termination and TiO2 termination). XPS analysis confirmed that water and carbon dioxide as adventitious carbon species present in air are chemically adsorbed on the STO surface, providing evidence of desorption process which persists until 550 °C. This condition is an important issue in order to obtain clean controlled interface between STO and deposited film for low temperature growth as for instance atomic layer deposition and integration of STO buffer layer on silicon. In situ SE commonly present in thin layer deposition systems is a powerful tool to monitor in situ surface contamination and decontamination temperature as it can be performed in situ even in operando.

Published
2016

48. Gene Regulatory Network Inference using ensembles of Local Multiple Kernel Models

Author

Fouchet, Arnaud, Delosme, Jean-Marc, d'Alché-Buc, Florence, Fouchet, Arnaud, Informatique, Biologie Intégrative et Systèmes Complexes (IBISC), Université d'Évry-Val-d'Essonne (UEVE), Algorithms and Models for Integrative Biology (AMIB ), Laboratoire d'informatique de l'École polytechnique [Palaiseau] (LIX), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Laboratoire de Recherche en Informatique (LRI), Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-CentraleSupélec-Centre National de la Recherche Scientifique (CNRS)-Inria Saclay - Ile de France, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Recherche en Informatique (LRI)

Subjects
[SDV.BIBS] Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], [INFO.INFO-LG]Computer Science [cs]/Machine Learning [cs.LG], [INFO.INFO-LG] Computer Science [cs]/Machine Learning [cs.LG], [INFO.INFO-BI]Computer Science [cs]/Bioinformatics [q-bio.QM], [SDV.BIBS]Life Sciences [q-bio]/Quantitative Methods [q-bio.QM], [INFO.INFO-BI] Computer Science [cs]/Bioinformatics [q-bio.QM]
Abstract

International audience; Reconstructing gene regulatory network from high-throughput data has many potential applications, from understanding a biological organism to identifying potential drug targets. It is also a notoriously difficult problem, tackled by many scientists with various methods. In this paper, we formulate GRN inference as a sparse regression problem. We decompose the prediction of a p-genes system in p different regression problems. For each gene (target gene), we train a kernel-based regression with feature selection, predicting the expression pattern of the target gene using all the other genes (input genes). The regression will give the importance of each input gene in the prediction of the target gene. We take this importance as an indication of a putative regulatory link. Putative links are then aggregated over all genes to provide a ranking of interactions, from which we infer the GRN. Furthermore, biological data are heterogeneous. The method we propose can learn from both steady-state and time-series data, using an ensemble method that can be applied to other regression model. Finally, we compare our method, called LocKING, to state-of-the-art methods on real and realistic datasets, which are widely spread in the GRN inference community. We show that our method is competitive against individual methods. Nevertheless, best results are obtained by integrating multiple methods. We show that using LocKING among other methods significantly enhances the accuracy of the network inferred.

Published
2013

49. Strong Magnetic Anisotropy of Epitaxial PrVO3Thin Films on SrTiO3Substrates with Different Orientations

Author

Kumar, Deepak, David, Adrian, Fouchet, Arnaud, Pautrat, Alain, Boullay, Philippe, Jung, Chang Uk, and Prellier, Wilfrid

Abstract

We have probed the structural and magnetic properties of PrVO3(PVO) thin films grown on the (001)-, (110)-, and (111)-oriented SrTiO3(STO) substrates. By changing the substrate orientation, the film out-of-plane orientation can be tuned to [110], [100]/[010], and [011]/[311], with different in-plane crystallographic variants. Accommodation of these variants on the different substrates implies different strain states, which have direct influence on the magnetic properties of PVO films. The magnetic moment of PVO films radically enhances from 0.4 μB/f.u. for STO(001) to 2.3 μB/f.u. for STO(111). While films on the (001)-oriented STO substrate display out-of-plane anisotropy, an in-plane anisotropy is observed for films grown on the (110)- and (111)-oriented STO substrates. In addition, a strong uniaxial magnetic anisotropy is also extracted for a partially relaxed film on the (110)-oriented STO substrate. Such findings can help oxide community for the better understanding of magnetic anisotropy in vanadate thin films, a subject that still suffer from significant lack of scientific investigations.

Published
2020
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50. Transfer of Epitaxial SrTiO3Nanothick Layers Using Water-Soluble Sacrificial Perovskite Oxides

Author

Bourlier, Yoan, Bérini, Bruno, Frégnaux, Mathieu, Fouchet, Arnaud, Aureau, Damien, and Dumont, Yves

Abstract

The integration of functional thin film materials with adaptable properties is essential for the development of new paradigms in information technology. Among them, complex oxides with perovskite structures have huge potential based on the particularly vast diversity of physical properties. Here, we demonstrate the possibility of transferring perovskite oxide materials like SrTiO3onto a silicon substrate using an environmentally friendly process at the nanoscale by means of a water-soluble perovskite sacrificial layer, SrVO3. Based on in situ monitoring atomic force microscopy and photoemission studies, we reveal that the dissolution is initiated from a strontium-rich phase at the extreme surface of SrVO3. The nanothick SrTiO3-transferred layer onto silicon presents appropriate morphology and monocrystalline quality, providing a proof of concept for the integration and development of all-perovskite-oxide electronics or “oxitronics” onto any Si-based substrate.

Published
2020
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