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Europhys. Lett.
Volume 68, Number 6, December 2004
Page(s) 846 - 852
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 30 November 2004
Europhys. Lett., 68 (6), pp. 846-852 (2004)
DOI: 10.1209/epl/i2004-10292-4

Quasiparticle properties of the possible superconductor materials $\chem{LiBC}$ and $\chem{NaBC}$

S. Lebègue1, B. Arnaud2, P. Rabiller2, M. Alouani1 and W. E. Pickett3

1  Institut de Physique et de Chimie des Matériaux de Strasbourg (IPCMS) UMR 7504 du CNRS - 23 rue du Loess, 67037 Strasbourg, France
2  Groupe Matière condensée et Matériaux (GMCM), Campus de Beaulieu Bât. 11A - 35042 Rennes cedex, France
3  Department of Physics, University of California - Davis, CA 95616, USA

received 13 September 2004; accepted 22 October 2004
published online 30 November 2004

The quasiparticle band structures within the GW approximation of the possible superconductors $\chem{LiBC}$ and $\chem{NaBC}$ are presented. The GW correction to the LDA is shown to be strongly dependent on the degree of orbital localization, and the overall correction cannot be reproduced by a rigid band shift as in conventional semiconductors. Precise values of the interband transitions for high-symmetry points in the Brillouin zone are given. The imaginary part of the self-energy which is related to the lifetime of quasiparticles, is presented in order to be compared with future experiments. Moreover, the ground-state properties of $\chem{LiBC}$ and $\chem{NaBC}$ are studied and it is shown that the bonding is partly covalent.

71.15.Mb - Density functional theory, local density approximation, gradient and other corrections.

© EDP Sciences 2004