First principles studies of structural, electronic, optical, elastic and thermal properties of Ag-chalcopyrites (AgInX2: X=S, Se)

First principles calculations for the structural, electronic, optical, elastic and thermal properties of the silver indium dichalcogenides (AgInX2: X=S and Se) have been reported using the full potential linearized augmented plane wave (FP-LAPW) method. In this approach, the recently developed density functional theory of Tran and Blaha is used along with the Wu-Cohen generalized gradient approximation (WC-GGA) for the exchange-correlation potential. Results were given for lattice constants, bulk modulus and its pressure derivative, band structures, dielectric constants and refractive indices. We have also computed the full elastic tensors (C11, C12, C13, C33, C44 and C66). The thermodynamical properties such as thermal expansion, heat capacity, Debye temperature, entropy, Grüneisen parameter, bulk modulus and hardness were calculated employing the quasi-harmonic Debye model at different temperatures (0–800 K) and pressures (0–8 GPa). Most of the investigated parameters are reported for the first time.