Electronic band structure and influence of uniaxial stresses on the properties of K2SO4 crystal: ab initio study

Influence of the uniaxial stresses on the electronic band structure, density of states, and optical properties of the potassium sulphate crystal β-K2SO4 have been studied in the framework of the density functional theory using the ab initio code CASTEP (CAmbridge Serial Total Energy Package). Increase of the band gap Eg of the crystal takes place for there crystallographical directions and for moderate uniaxial stresses, σ < 1.5 GPa. Dependencies of principal refractive indices (nx, ny, nz) upon uniaxial stresses (σx, σy, σz) are discussed together with other features of electronic structure of the crystal.