Structural, electronic, optical and elastic properties of AgMO2 (M = K, Rb, Cs): ab initio investigation

Silver alkali oxides (AgMO2; M = K, Rb, Cs) properties are investigated in depth via pseudo-potential plane-wave (PP-PW) scheme within the density functional theory (DFT) framework. The reflectivity, loss function and all the elastic properties of AgKO2, AgRbO2, AgCsO2 compounds are newly studied here. As unveiled by the band structure the AgMO2 materials are indirect bandgap semiconductors. The density of states illustrates the covalent character of silver oxygen bonds (Ag-O). Moreover, the notable contribution of O-2p in the edge of the valence band provokes the delocalization of the holes, consequently improving the p-type conductivity in the studied compounds. Optically analyzed, our systems show birefringent behavior, with high positive Delta n(0), allowing them to be candidate in non-linear optical devices applications. The obtained elastic constants state that our materials are mechanically stable, with a pronounced anisotropic nature. Finally, from the thermal investigation, the three oxides AgKO2, AgRbO2 and AgCsO2 have lower thermal conductivity, synonymous of lower melting temperature.