Ab-initio study of the structural and optoelectronic properties of BaSe1-xSx alloys

Abstract Structural and optoelectronic properties of BaSe and BaS compounds and their ternary mixed crystals BaSe1-xSx for 0 ≤ x ≤ 1 which crystallize in NaCl-type structure (B1) have been studied with density functional theory (DFT) based full-potential linearized augmented plane wave (FP-LAPW) methodology. Structural properties of the binary compounds and their ternary alloys have been investigated using both generalized-gradient approximations (WC-GGA) developed by Wu-Cohen and (PBE-GGA) developed Perdew-Burke-Ernzerhof. For the electronic properties, in addition to WC-GGA, the recently developed modified Becke and Johnson (mBJ) potential was also used. The concentration dependences of lattice parameter, bulk modulus and band gap for the alloys exhibit nonlinearity. Optical properties of the alloys have been calculated in terms of their respective dielectric function, refractive index, and reflectivity.