A DFT study of the effect of strain on the structural and electronic properties of perovskite APbBr3 (A = K, Rb, and Cs)

Abstract

This study investigated the physical properties of perovskite compounds with the general formula APbBr3 (A = K, Rb, and Cs), Applying the Density Functional Theory (DFT) method. For these APbBr3 crystals, the optimum lattice constants are determined, serving as the basis for the computations. In these calculations, pseudopotential by GGA-PBE correlation exchange functional is used. The band gap, Density of States (DOS), Projected Density of States (PDOS), charge density, and charge difference caused by changing the charge of each element in the primary state or the lattice constant in one and three directions are estimated. The energy gaps for KPbBr3, RbPbBr3, and CsPbBr3 for GGA-PBE pseudopotentials were 1.7436, 1.7746, and 1.7815 eV and for CsPbBr3 with optimized and experimental lattice constants, 1.78 eV and 1.81 eV, respectively. Also, computation results showed that in some cases (the size of the lattice constant change, for example, was 10%), there were critical points such as conductivity, topological insulator and n-type semiconductor. Finally, studying the electronic structure of these perovskite by changing the lattice constant is a new and novel method in its own right. Also the electronic structure of this perovskite by changing the lattice constant has not been considered in other studies.