Alloying effect in the III-As-Sb ternary systems

First-principles pseudopotential plane-wave calculations are used to investigate the alloying effect on the structural and electronic properties of cubic arsenides antimonides III-As-Sb alloys. The focus is on the determination of the variation of the lattice parameter and the optical gap bowing of these alloys. We found that the Vegard's law almost perfectly met the variation of the lattice parameter. The calculated bowing parameter of the optical band gap, i.e. the nonlinearity noticed in the variation, is in agreement with the previous theoretical and experimental works. Results show that the bowing parameter of the III-As-Sb alloys has a remarkable contribution due to the structural relaxation effects and a relatively weak charge transfer effect.