Computational study on structural, elastic, mechanical and optical properties of K2AgAs ternary semiconductor compound

In this study, the structural, electronic, elastic, mechanical, and optical properties of a new Zintl phase K2AgAs ternary semiconductor compound have been investigated by the first-principles method using the plane-wave self-consistence field method. A triangulation of different exchange-correlation functionals, including local density approximation-LDA-PZ, generalized gradient approximation (GGA)-Q2D, GGA-BLYP, GGA-Perdew–Burke–Ernzerhof (PBE), GGA-PBESol, and GGA-revPBE, have been utilized to predict the properties of the material. The computed structural properties predicted that the K2AgAs compound is thermodynamically stable, and the lattice parameters are consistent with the reported experimental values. The electronic properties show that the bandgap ranges between 0.6645 and 1.1915 eV, while the conduction and valence bands are formed mainly through the hybridization of the As-2p, Ag-2p and Ag-3d, As-2p states, respectively, with other states making minimal contribution. From the calculation of elastic properties, K2AgAs were predicted to be mechanically stable. Notably, K2AgAs has been predicted to absorb light within the ultraviolet-visible regime. Owing to their good thermodynamic and mechanical stability, wide coverage of absorption in the UV-Vis region of the solar spectrum, and narrow bandgaps, K2AgAs can be formed/synthesized and applied as the active photoactive material in solar cells and other photovoltaics.