Theoretical investigations of structural, electronic and optical properties of ZnGeAs2 under different pressures

The plane wave pseudo-potential method within density functional theory (DFT) has been used to investigate the structural, electronic and optical properties of ZnGeAs2 chalcopyrite semiconductor. The lattice constants are calculated from the optimized unit cells and compared with the experimental values. The band structure, total density of states (TDOS) and partial density of states (PDOS) have been discussed. The optical properties such as dielectric function, refractive index, optical reflectivity, extinction coefficient, electron energy loss spectrum and absorption spectra have been studied under three different hydrostatic pressures 0, 20 and 40 GPa in the energy range 0-20 eV. The calculated values of all parameters are compared with the available experimental values and the values reported by different workers. A fairly good agreement has been found between them.