First principles computation of insulator–semiconductor–metal transition and its impact on structural, elastic, mechanical, anisotropic and optical properties of CsSrF3 under systematic static isotropic pressure

Abstract

ABSTRACT A fluro-perovskite Cesium Strontium Fluoride (CsSrF3) has been explored, for the first time, in terms of structural, elastic, mechanical, anisotropic, electronic and optical characteristics under stress ranging from 0 to 513 GPa. According to structural properties, there is no phase transition and the compound remains in its cubic structure. The mechanical features show that the material is stable except at 0 and 500–513 GPa. Moreover, the compound is stiffer, more resistant to permanent deformation and brittle up to a stress of 0–20 GPa before transitioning to a ductile state. The indirect band gap of CsSrF3 is 5.709 eV at 0 GPa, but it increases to a maximum value of 7.155 eV at 30 GPa, and further high-pressure results in a band gap of 0 eV. The presence of high external pressure proved to be very excellent due to the transition of the indirect band gap to the direct band gap and because of the insulator to semiconductor and then towards the conductor changes. To check the effect of pressure on optical properties, different optical parameters have been computed. Due to the existence of its absorption edge in the UV region, CsSrF3 would be a perfect material as a UV detector.