Ab initio study of structural, electronic and optical properties of ordered group-IV binary alloy Ge0.5Sn0.5

We have applied the full-potential linearized augmented plane wave (FP-LAPW) method to study the structural, electronic and optical properties of ordered semiconductor alloy Ge0.5Sn0.5 using the generalized gradient approximation (GGA) for the exchange and correlation potential. Our results are in agreement with previous theoretical and experimental studies on this important semiconductor compound. The effects of spin–orbit coupling on the structural properties and the band structure have been examined. The pressure dependence of the energy gap for the alloy is presented. Also, the origin of the structures in the optical spectra are discussed.