Abstract
Structural parameters, elastic constants, electronic structure and optical functions of the ternary tetragonal chalcogenides KAlTe2 and KInTe2 are predicted via ab initio calculations. The calculated structural parameters and interatomic distances agree very well with the existing experimental results. The computed band structures show that the two studied materials are semiconductors with indirect band-gaps. The computed partial density of states diagrams, charges transfer and distribution of charge density show that the interatomic bonds are mainly of a covalent nature. The calculated elastic constants indicate that the title compounds are mechanically stable and elastically strongly anisotropic. The calculated optical spectra for both explored compounds exhibit a significant optical anisotropy. Both compounds have a low absorption in the visible range compared to the infrared (IR) domain. The refractive index spectrum of KInTe2 is more anisotmpic than that of KAlTe2.