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 AgBX 3 (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 AgBX 3 show that AgBeBr 3 , AgMgBr 3 , and AgMgI 3 compounds are indirect bandgap semiconductors, while AgBeI 3 has metallic property. The valence band of the AgBX 3 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 AgBX 3 were analyzed in the energy range 0–30 eV. It is found that AgBX 3 has high transparency in visible light range and good ultraviolet light absorption ability, which reflects that AgBX 3 can be employed as window and lens materials in visible light range and ultraviolet optical devices.