First principles studies of the structural, electronic and optical properties of LiInSe2 and LiInTe2 chalcopyrite crystals

•Structural, electronic and optical properties of LiInSe2 and LiInTe2 were calculated.•Direct character of the band gaps was determined.•Dependence of the refractive index on the wavelength was calculated.

Detailed first principles calculations of the structural, electronic and optical properties of two representatives of the chalcopyrite group of compounds (LiInSe2 and LiInTe2) are reported in the present paper. Both materials are shown to be the direct band gap semiconductors. Analysis of the electronic properties showed that the degree of covalency increases if Se is substituted by Te. Calculations of the optical properties of both crystals allowed to get reliable approximation of the refractive index as a function of the wavelength. All calculated results were compared with the available experimental data; good agreement was demonstrated.