Pressure dependence of electronic properties in zinc-blende-like SiGe compound

We have performed an empirical pseudo-potential study of the electronic properties of zinc blende-like SiGe compound under pressure. A simple method for combining single element pseudopotential model into model for compound is investigated. Using parameters fitted to silicon and germanium band structures, test cases for SiGe band structure and the various quantities including energies levels, density of states, charge density, ionic character, transverse effective charge and refractive index show excellent results compared to SiC. The electronic charge density is used to study the modification of the bonding of this compound with respect to different pressures. The distribution of the valence charge density suggests that the bonding in SiGe is less ionic than in SiC. Our results also show that:SiGe present the same anomalous behavior for the effective charge found in SiC. (C) 1998 Elsevier Science Ltd. All rights reserved.