Ab initio study of structural, electronic and optical properties of Ca1−xSrxS compounds

Full-potential linearized augmented plane wave method (FP-LAPW) within density functional theory has been used to calculate structural, electronic and optical properties of Ca_1−xSr_xS, an alkali earth chalcogenide, with varying compositional parameter x in the range 0<x<1. Whereas the structural properties are discussed in terms of charge transfer between the two cations, calculated electronic band structure and density of states have been analyzed in terms of contribution from the S p, Ca d and Sr d states. Furthermore, we have calculated some optical properties such as real and imaginary parts of dielectric constant, ε(ω), and the calculated results have been discussed in comparison with the existing experimental data and other theoretical calculations.