Energy band structure of strained crystals: Pseudopotential calculations for Ge and Si with trial calculations for GaAs and CdTe

Abstract

A simple model pseudopotential scheme is presented for calculating the effects of strain on the energy-band structure of diamond and zinc-blende structure crystals. Spin-orbit coupling is included in the calculation by using an empirical approach to describe the spin-orbit interaction throughout the Brillouin zone by a single constant for each different atom in a unit cell. Good numerical agreement with experimentally determined deformation potential constants for silicon and germanium is obtained. Quantitative results for a variety of nonlinear effects are also obtained. For GaAs and CdTe agreement with experiment is poorer and it is suggested that this is caused by poor initial values for the pseudopotential form factors. This indicates that deformation potential constants may be sensitive parameters to use for determining pseudopotential form factors when the empirical pseudopotential technique is being employed.