Etude des propriétés structurales, élastiques et électroniques des pérovskites

Abstract

In our work, we studied the structural, elastic and electronic properties of cubic perovskites CaSnO3, SrSnO3 and BaSnO3. We used the Plane Wave Augmented and Linearized with Total Potential (FP-LAPW) method within the framework of the DFT density functional theory implemented in the Wien2k code. The exchange and correlation potential was treated by different approximations WC-GGA and TB-mBJ. The results of the calculation showed that these perovskites are indirect gap semiconductors (Γ-M). The top of the valence band resulting mainly from the p states of the oxygen O atom, and the bottom of the conduction band resulting mainly from the d states of the A atom with respect to SrSnO3 and BaSnO3 perovskites, and s-states of the A atom with respect to the CaSnO3 compound. CaSnO3, SrSnO3 and BaSnO3 are mechanically stable and rigid where the degree of rigidity of these materials decreases in the following order: CaSnO3, BaSnO3, SrSnO3. We have also classified them, according to the Poisson modulus and the Pugh ratio, into brittle materials, except SrSnO3 which is a ductile material. We also compared our results with available theoretical and experimental results.