Abstract
This study reports theoretical calculations of structural, elastic, electronic and optical properties of inter-alkaline chalcogenides NaLiSe and NaLiTe. It is found that the structural parameters are in accordance with both theoretical and experimental values. The low values of the elastic moduli indicate that NaLiSe and NaLiTe are soft in nature. The analysis of the bulk modulus to shear modulus (B/G) ratio classifies NaLiSe as ductile while NaLiTe as brittle. The electronic properties reveal their semiconductor nature with a direct wide band gap of 2.98 and 2.75 eV for NaLiSe and NaLiTe, respectively, besides confirming their ionic behavior as manifested by the charge density distributions. The dielectric function, refractive index, reflectivity, optical conductivity, absorption spectra, extinction coefficient, and energy-loss spectrum are determined and discussed. This is the first quantitative theoretical prediction of the elastic and optical properties of these compounds and awaits experimental confirmation.
Graphical abstract