Etude des propriétés physiques des pérovskites oxydes SrMO3 (M = Ti et Sn) et hydrides XCaH3 (X = Cs et Rb)

Abstract

In this study, the pseudopotential-plane wave (PP-PW) approach, based on density functional theory (DFT) with the generalized gradient approximation (GGA), was employed. A structural, elastic, electronic, and optical investigation of the oxide perovskites SrMO3 (M = Ti, Sn) and the hydride perovskites XCaH3 (X = Cs, Rb) is presented. The equilibrium lattice parameters are in good agreement with experimental data for both types of perovskites. These perovskites remain stable within the pressure range considered. SrMO3 compounds exhibit an indirect band gap at the Fermi level, while XCaH3 compounds exhibit a direct band gap. An analysis of the effect of pressure on the static dielectric function and the static refractive index reveals that both parameters are inversely proportional to the fundamental band gap for both types of perovskites. Furthermore, the absorption, reflectivity, refractive index, extinction coefficient, and energy loss were calculated.