Ab initio calculation of mechanical, electronic and optical characteristics of chalcogenide perovskite BaZrS₃ at high pressures

A theoretical examination of the structural, elastic, electronic and optical properties of the chalcogenide perovskite BaZrS₃ under pressures of 0 and 20 GPa was performed using density functional theory ab initio calculations. The lattice constants of the BaZrS₃ structure are well reproduced from our first-principles calculations and are in excellent agreement with experimental measurements. Moreover, the values of mechanical parameters, such as the elastic constant, increased under applied pressure. The electronic parameters indicate that the chalcogenide perovskite BaZrS₃ has a direct band gap of 1.75 eV. To understand the optical response, the real and imaginary parts of the dielectric function of BaZrS₃ have been studied, as well as the absorption coefficient, reflectivity and extinction coefficient. The induced pressure is found to enhance the optical parameters in the different energy regions. Our calculations predict that the studied chalcogenide perovskite BaZrS₃ could be a candidate in photovoltaic, optoelectronic and mechanical applications.