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3 results on '"Ba8si46"'

1. Structural, electronic, phonon and thermodynamic properties of hypothetical type-VIII clathrates Ba8Si46 and Ba8Al16Si30 investigated by first principles.

Author

Norouzzadeh, Payam, Myles, Charles W., and Vashaee, Daryoosh

Subjects
*BARIUM compounds, *THERMODYNAMICS, *ELECTRIC properties of metals, *PHONONS, *PREDICTION models, *BAND gaps, *ELASTIC constants
Abstract

Highlights: [•] Properties of hypothetical clathrates-VIII Ba8Si46 and Ba8Al16Si30 are predicted. [•] Replacing some Si with Al decreases the band gap and the elastic constants. [•] Both materials have degenerate semiconducting or metallic electronic properties. [•] Both clathrates are energetically more stable than their constituent bulk elements. [•] Both materials have phonon band gaps. [ABSTRACT FROM AUTHOR]

Published
2014
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2. Superconductivity in Doped sp3 Semiconductors: The Case of the Clathrates

Author

Antonino Marco Saitta, J. Beille, Jacques Marcus, Vladimir Timoshevskii, Bruno Masenelli, Shoji Yamanaka, Gian-Marco Rignanese, Bernard Barbara, Damien Connétable, Xavier Blase, Patrice Mélinon, Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Laboratoire Louis Néel (LLN), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etudes des Propriétés Electroniques des Solides (LEPES), Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique de Grenoble (INPG)-Université Joseph Fourier - Grenoble 1 (UJF), Laboratoire de Physique de la Matière Condensée (LPMC), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Unité de Physico-Chimie et de Physique des Matériaux (UCL PCPM), Université Catholique de Louvain = Catholic University of Louvain (UCL), Department of Applied Chemistry (Faculty of Engineering, Hiroshima University), Hiroshima University, Centre National de la Recherche Scientifique - CNRS (FRANCE), Hiroshima University (JAPAN), Institut polytechnique de Grenoble (FRANCE), Fondation Nanosciences (FRANCE), Université Pierre et Marie Curie, Paris 6 - UPMC (FRANCE), Université Claude Bernard-Lyon I - UCBL (FRANCE), Université Joseph Fourier Grenoble 1 - UJF (FRANCE), Katholieke Universiteit Leuven - KU LEUVEN (BELGIUM), Laboratoire de Physique de la Matière Condensée et Nanostructures ( LPMCN ), Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Laboratoire Louis Néel ( LLN ), Centre National de la Recherche Scientifique ( CNRS ), Laboratoire d'Etudes des Propriétés Electroniques des Solides ( LEPES ), Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut National Polytechnique de Grenoble ( INPG ) -Centre National de la Recherche Scientifique ( CNRS ), Laboratoire de Physique de la Matière Condensée ( LPMC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Unité de Physico-Chimie et de Physique des Matériaux ( UCL PCPM ), Université Catholique de Louvain ( UCL ), Department of Applied Chemistry ( Faculty of Engineering, Hiroshima University ), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Silicon, Materials science, clathrates, Compound, Ab initio, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, Electron-Gas, 74.70.Wz, 71.15.Mb, 74.62.Bf, 74.62.Fj, 01 natural sciences, Condensed Matter::Materials Science, diamond, Ab initio quantum chemistry methods, Condensed Matter::Superconductivity, [ PHYS.COND.CM-S ] Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], Ba8si46, Crystal, 0103 physical sciences, 010306 general physics, Pseudopotentials, Matière Condensée, Coupling constant, Superconductivity, Condensed matter physics, Physique, ab initio, superconductivity, Doping, Temperature, BCS theory, 021001 nanoscience & nanotechnology, [PHYS.COND.CM-S]Physics [physics]/Condensed Matter [cond-mat]/Superconductivity [cond-mat.supr-con], chemistry, Density functional theory, Si, 0210 nano-technology, Principles
Abstract

International audience; We present a joint experimental and theoretical study of the superconductivity in doped silicon clathrates. The critical temperature in Ba8@Si–46 is shown to strongly decrease with applied pressure. These results are corroborated by ab initio calculations using MacMillan's formulation of the BCS theory with the electron-phonon coupling constant lambda calculated from perturbative density functional theory. Further, the study of I8@Si–46 and of gedanken pure silicon diamond and clathrate phases doped within a rigid-band approach show that the superconductivity is an intrinsic property of the sp3 silicon network. As a consequence, carbon clathrates are predicted to yield large critical temperatures with an effective electron-phonon interaction much larger than in C60.

Published
2003
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3. Tailoring band gap and hardness by intercalation: An ab initio study of I-8@Si-46 and related doped clathrates

Author

Connétable, D., Timoshevskii, V., Artacho, E., Blase, X., Centre National de la Recherche Scientifique - CNRS (FRANCE), University of Cambridge (UNITED KINGDOM), Université Claude Bernard-Lyon I - UCBL (FRANCE), Laboratoire de Physique de la Matière Condensée et Nanostructures (LPMCN), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon, Department of Earth Sciences [Cambridge, UK], and University of Cambridge [UK] (CAM)

Subjects
Condensed Matter::Materials Science, Superconductivity, Pseudopotential, Condensed Matter::Superconductivity, Matériaux, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], SI, BA8SI46, 71.20.Tx, 62.20.-x, 81.05.Zx, 82.75.-z, Electronic-structure
Abstract

We present an ab initio study of the structural and electronic properties of the recently synthesized I-8@Si-46 clathrate which is shown to be a degenerate p-type doped system. The intercalation significantly opens the band gap to a 1.75 eV value within the density functional theory. We study further the intercalation by other neighboring elements. A quasiparticle study reveals that such systems can display a band gap in the ``green-light'' energy range. Finally, we show that the bulk modulus can be increased to values equivalent to the one of the diamond phase.

Published
2001
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