First-principles calculations of the structural, mechanical, electronic, and optical properties of BaX2 (X=O, S, Se and Te) compounds

Abstract

We used the first-principles to study the structural, mechanical, electronic, optical properties and phonon of alkali earth-metal Ba dichalcogenide BaX2 (X = O, S, Se and Te). First, our calculated lattice constants are in good agreement with the known experimental values. Secondly, the binding and formation energies, bulk modulus, Young's modulus, Poisson's ratio, Debye temperature, sound velocity and phonon dispersion curves of BaX2 compounds are given. Through basic physical property research, we found that the monoclinic structure of BaX2 (C2/c) is very likely to exist. The modulation of elastic, electronic and optical properties of this system may be achievable. Furthermore, both elastic and optical properties indicate that BaX2 is anisotropic. Finally, the electronic properties are studied by density of states and Mulliken population, indicating that all the compounds are mainly ionic properties.