First-principles investigation on the structure, electronic, mechanical and optical properties of silver based perovskites AgBX₃ (B=Be, Mg; X=Br and I)

Abstract

The structure, mechanical, electronic and optical properties of Ag-based halides AgBX3 (B=Be, Mg; X=Br, I) were studied using first-principles approach for the first time. The elastic constants reveal that these materials are mechanical stability. The results of Pugh's ratio, bulk modulus, Poisson's ratio and anisotropy coefficients exhibit that these compounds are ductility, anisotropy, and ionic properties, and the hardness of beryllium compounds is larger than that of magnesium compounds. The band structure and density of states for AgBX3 show that AgBeBr3, AgMgBr3 and AgMgI3 compounds are indirect bandgap semiconductors, while AgBeI3 has metallic properties. The valence band of the AgBX3 is mainly dominated by Ag-d and X-p orbital electrons, and the conduction band is composed predominantly of B-p and X-s orbital electrons. The optical properties of AgBX3 were analyzed in the energy range 0-30 eV. It is found that AgBX3 has high transparency in visible light range and good ultraviolet light absorption ability, which reflects that AgBX3 can be employed as window and lens materials in visible light range and ultraviolet optical devices.