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Your search keyword '"CHAUBET, Christophe"' showing total 12 results
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12 results on '"CHAUBET, Christophe"'

1. Miles' mechanism for generating surface water waves by wind, in finite water depth and subject to constant vorticity flow

Author

Kern, Norbert, Chaubet, Christophe, Kraenkel, Roberto, and Manna, Miguel

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

The Miles theory of wave amplification by wind is extended to the case of finite depth h and a shear flow with (constant) vorticity {\Omega}. Vorticity is characterised through the non-dimensional parameter {\nu} = {\Omega} U_1 /g, where g the gravitational acceleration, U_1 a characteristic wind velocity and k the wavenumber. The notion of 'wave age' is generalised to account for the effect of vorticity. Several widely used growth rates are derived analytically from the dispersion relation of the wind/water interface, and their dependence on both water depth and vorticity is derived and discussed. Vorticity is seen to shift the maximum wave age, similar to what was previously known to be the effect of water depth. At the same time, a novel effect arises and the growth coefficients, at identical wave age and depth, are shown to experience a net increase or decrease according to the shear gradient in the water flow.

Published
2021

2. Anharmonicity and asymmetry of Landau levels for a two-dimensional electron gas

Author

Bonifacie, Stephane, Chaubet, Christophe, Jouault, Benoit, and Raymond, Andre

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We calculate the density of states of a two dimensional electron gas located at the interface of a GaAlAs/GaAs heterojunction. The disorder potential which is generally created by a single doping layer behind a spacer, is here enhanced by the presence of a second delta doped layer of scatterers which can be repulsive or attractive impurities. We have calculated the density of states by means of the Klauder's approximation, in the presence of a magnetic field of arbitrary strength. At low field either band tails or impurity bands are observed for attractive potentials, depending on the impurity concentration. At higher field, impurity bands are observed for both repulsive and attractive potentials. We discuss the effect of such an asymmetrical density of states on the transport properties in the quantum Hall effect regime., Comment: 22 pages, 12 figures. submitted to Phys. Rev. B

Published
2005
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6. Conduction electrons localized by charged magnetoacceptors A2- in GaAs/GaAlAs quantum wells

Author

Kubisa, M, Ryczko, K., Bisotto, Isabelle, CHAUBET, Christophe, RAYMOND, Andre, Zawadzki, W, University of Wrocław [Poland] (UWr), Wroclaw University of Science and Technology, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Polish Academy of Sciences (PAN), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)

Subjects
Condensed Matter::Materials Science, [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall]
Abstract

International audience; A variational theory is presented of A1− and A2− centers, i.e., of a negative acceptor ion localizing one and two conduction electrons, respectively, in a GaAs/GaAlAs quantum well in the presence of a magnetic field parallel to the growth direction. A combined effect of the well and magnetic field confines conduction electrons to the proximity of the ion, resulting in discrete repulsive energies above the corresponding Landau levels. The theory is motivated by our experimental magnetotransport results which indicate that, in a heterostructure doped in the GaAs well with Be acceptors, one observes a boil-off effect in which the conduction electrons in the crossed-field configuration are pushed by the Hall electric field from the delocalized Landau states to the localized acceptor states and cease to conduct. A detailed analysis of the transport data shows that, at high magnetic fields, there are almost no conducting electrons left in the sample. It is concluded that one negative acceptor ion localizes up to four conduction electrons.

Published
2015
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7. 'Système à rendement élevé de production d’électricité à partir d’énergie solaire récoltée par des capteurs solaires thermiques et utilisant un moteur ditherme à source de chaleur externe'

Author

Chaubet, Christophe, Chenaud, Boris, Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Aigle, L2c

Subjects
[SPI.NRJ]Engineering Sciences [physics]/Electric power, énergie solaire thermiquepompe à chaleurmoteur Stirling, [SPI.NRJ] Engineering Sciences [physics]/Electric power
Abstract

Nous publions un Brevet sur la production optimisée d'énergie électrique à partir d'eau chaude obtenue par chauffage solaire thermique. C'est une solution adaptée aux maisons individuelles.

Published
2013

8. Two-electron states localized by charged acceptors in GaAs/GaAlAs quantum wells in ultra-quantum regime of magnetic fields

Author

Bisotto, I, CHAUBET, Christophe, Raymond, Andre, Zawadzki, W, Kubisa, M, Aigle, L2c, Laboratoire Charles Coulomb (L2C), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Polish Academy of Sciences (PAN), and University of Wrocław [Poland] (UWr)

Subjects
[PHYS.COND.CM-MSQHE] Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], [PHYS.QPHY]Physics [physics]/Quantum Physics [quant-ph], [PHYS.COND.CM-MSQHE]Physics [physics]/Condensed Matter [cond-mat]/Mesoscopic Systems and Quantum Hall Effect [cond-mat.mes-hall], [PHYS.QPHY] Physics [physics]/Quantum Physics [quant-ph]
Abstract

International audience; We demonstrate theoretically that bound acceptors states of a two dimensional electron gas in quantizing magnetic field can localize two electrons on a same site. We calculate the energies and wave functions of the second quantum state, and show that they are close to calculations of the first quantum state found previously.

Published
2013

9. Nonlinear dependence of the magnetophotoluminescence energies of asymmetric GaAs/Ga0.67Al0.33As quantum wells on an external magnetic field

Author

Zawadzki, W., Bonifacie, S., Juillaguet, Sandrine, Chaubet, Christophe, Raymond, Andre, Meziani, Y. M., Kubisa, M., Ryczko, K., Groupe d'étude des semiconducteurs (GES), and Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS)

Subjects
SINGLE HETEROJUNCTIONS, 2-DIMENSIONAL ELECTRON-GAS, REGIME, DENSITY, MAGNETOLUMINESCENCE, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], LUMINESCENCE ENERGY, PHOTOLUMINESCENCE, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, MAGNETOOPTICS, OSCILLATION
Abstract

Nonlinear dependence of the magnetophotoluminescence (MPL) energies in modulation-doped asymmetric GaAs/Ga0.67Al0.33As quantum wells of different widths are investigated experimentally and theoretically as functions of an external magnetic field. The investigated structures have only one electric subband populated with electrons. Contrary to the theoretical descriptions existing in the literature and based on the oscillations of screening, the observed maxima of MPL energies do not occur at integer filling factors and do not change into minima for higher well widths. We interpret our observations assuming that the oscillations of MPL energies are due to an oscillatory electron transfer between a GaAs well and a reservoir outside the well. We obtain a very good description of the experimental data concerning both the maxima positions and the oscillation amplitudes for different well widths and electron densities. Our interpretation is corroborated by the quantum Hall data obtained on the same samples.

Published
2007
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10. L'Option Sciences : un atout pour le dialogue entre disciplines

Author

Andral, Luc, Sabir, Abdallah, Soulier, Fabienne, Chaubet, Christophe, Noguès, Maryse, Henn, François, Geniet, Frédéric, Terki, Ferial, Théret, David, Groupe d'étude des semiconducteurs (GES), Université Montpellier 2 - Sciences et Techniques (UM2)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Institut de Chimie du CNRS (INC)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Laboratoire de Physique Théorique et Astroparticules (LPTA), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Institut de Mathématiques et de Modélisation de Montpellier (I3M), Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Montpellier (UM), Théret, David, Centre National de la Recherche Scientifique (CNRS)-Université Montpellier 2 - Sciences et Techniques (UM2), and Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC)

Subjects
[SHS.EDU]Humanities and Social Sciences/Education, [SHS.EDU] Humanities and Social Sciences/Education, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2006

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