An ab-initio study on the physical properties of double perovskite Cs2AgXBr6 (X=S, Te, Se)

Cs2AgXBr6 (X = S, Se, and Te) double perovskite structural, electronic, and optical properties were investigated using the density functional theory (DFT) method combined with various correlation potentials such as TB-mBJ, LDA, PBE, WC, and hybrid functionals (YS-PBE0). The calculated structural and elastic properties revealed that the Cs2AgXBr6 compounds are elastically stable, ductile, anisotropic, and ionically bonded. Both Poisson ratio and Pugh ratio confirm that Cs2AgXBr6 (X = S, Te, Se) compounds are ductile. The calculated density of States (DOS) and the electronic band structures of the investigated compounds display zero band gaps for these compounds. Therefore, the calculated electronic properties of these compounds indicate their metallic nature. The calculated optical transmittance shows the transparent behaviors of studied compounds.