First-principles investigation of electronic properties of GaAs$_{x}$Sb$_{1-x}$ ternary alloys

Compositional variations in GaAs based ternary alloys have exhibited wide range alterations in electronic properties. In the present paper, first-principles study of GaAs$_{x}$Sb$_{1-x}$ ternary alloys have been presented and discussed. Density functional theory (DFT) computation based on the full-potential (linearized) augmented plane-wave (FP-LAPW) method has been utilized to calculate the Density of States (DOS) and the band structure of ternary alloys GaAs$_{x}$Sb$_{1-x}$ ($x$ = 0, 0.25, 0.50, 0.75, 1).The calculations were performed using the exchange-correlation energy functional from Perdew, Burke, and Ernzerhof, a generalized-gradient approximation (GGA-PBE) and Becke-Johnson exchange potential with local-density approximation (BJLDA) available within the framework of WIEN2k code. As compared to PBE, the results obtained from BJLDA are in close agreement with other experimental works. The DOS results show a reduction in bandgap as the Sb fraction is increased in GaAs$_{x}$Sb$_{1-x}$ ternary alloys. The bandgap obtained by PBE and BJLDA are found to deviate from Vegard's law, i. e., it doesn't vary linearly with composition. However, the bandgap obtained by BJLD is found to closely match Vegard's law when the bowing parameter is considered.