Reduced symmetry and the band structure of semiconductor alloys.

Abstract

It is suggested that the neglect of the reduced local symmetry at some sites in alloys can be a serious shortcoming in the calculation of alloy band structures. A phenomenological scheme which takes account of the reduced local symmetry while preserving long-range order through the virtual-crystal approximation is described for calculating the band structure of alloys. It is shown that the method leads to an overall band structure similar to the corresponding virtual-crystal approximation but gives better agreement with experiment for the splitting of the valence bands at \ensuremath{\Gamma}.