Fermi surface, bonding, and pseudogap in MoSi2.

Andersen O.K., Jepsen O., Antonov Vl.N., Antonov V.N., Yavorsky B.Yu., Perlov A.Ya., Shpak A.P.

The electronic structure and Fermi surface of molybdenum disilicide has been calculated using local-density functional theory (LDA) and the linear muffin-tin orbital method (LMTO). The energy bands are analyzed in detail for their orbital character. Our explanation for the presence of a pseudogap after the seventh band is that the two Si s bands lie low and that there are five Mo d-Si p pair bands. The configuration is approximately Mo 4d5 Si2 3s2/3p2.5. An explanation in terms of directed bond-orbitals was not achieved. The calculated angular dependence of the extremal Fermi surface cross-section areas are in good qualitative agreement with de Haas-van Alphen (dHvA) measurements. However, in order to obtain quantitative agreement, the Mo dx(2-y(2)) orbital energy has to be shifted upwards by 0.41 eV and the Mo dxy energy downwards by 0.20 eV. This deficiency is ascribed to the use of a local exchange-correlation potential.

Physica B, 204 65-82, 1995.

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