Electronic structure of ternary semiconductor alloys: CPA calculations using sp³s^* bandstructures

Coherent potential approximation (CPA) calculations of the electronic structure of the III-V ternary alloys GaAs_1-x P_x, Ga_x In_1-x As, Ga_x Al_1-xAs, Ga_x In_1-x P, and GaSb_1-xP_x are reported. Results are presented for the CPA self-energies, state densities, and band-bowing functions for these materials. The calculations utilize the sp³s^* bandstructures as input into the Chen and Sher CPA formalism. The present work is the first utilization of these bandstructures in CPA calculations for ternary alloys and the first CPA treatment ofGaSb_1-xP_x. In qualitative agreement with previous studies, the results of these calculations show that alloy disorder effects are small for GaAs_1-xP_x, of moderate importance for Ga_xIn_1-xAs and Ga_xAl_1-xAs, and relatively large for Ga_xIn_1-xP. However, such effects are found to be significant for GaSb_1-xP_x, with this alloy predicted to be in the strong scattering regime.