Electronic structure of the pseudobinary semiconductor alloy Ga_xAl_{1 - x}Sb

A method for calculating the detailed electronic properties of the pseudobinary semiconductor alloy Ga_xAl_1-xSb os presented. The technique begins with realistic band structures obtained for the constituent compounds by fitting the band gap symmetry point energies to experimental data within the pseudopotential scheme. Then the virtual crystal approximation, which incorporates compositional disorder as an effective potential, is used to calculate the alloy band structures and charge densities. A detailed comparison between the theoretical predictions and experimental data demonstrates the quantitative nature of the method. The bowing parameters for the Λ, X and L gaps and the direct-to-indirect band gap cross-over concentrations are in good agreement with the experimental results.