Phase stability, mechanical and optoelectronic properties of lanthanum chromite-based perovskite oxide

The structural, magnetic, electronic, optical and mechanical properties of lanthanum chromite LaCrO 3 were investigated in cubic (Pm-3m) and orthorhombic (Pbnm) phases by the first-principles method based on the density functional theory. In this study, the WC-GGA with additional Hubbard potential U and Tran–Blaha-modified Becke–Johnson potential (TB-mBJ) were used. The structure optimization was accomplished for ferromagnetic (FM), A-type (A-AFM), C-type (C-AFM) and G-type (G-AFM). Both O-LaCrO 3 and C-LaCrO 3 phases were stable in the G-AFM state. The density of states and band structure revealed the existence of a wide band gap calculated with GGA + U and TB-mBJ, these two methods provide the accurate results for the band gap which are in good agreement with experimental values. The dielectric functions and optical proprieties were also calculated such as the absorption coefficient, refractivity index and the energy loss function. The elastic properties such as bulk modulus, shear modulus, Young’s modulus and Poisson’s ratio as well as the anisotropic factors were investigated. It has been shown that O-LaCrO 3 and C-LaCrO 3 phases were mechanically stable. Finally, the average sound velocity and the Debye temperatures of LaCrO 3 were evaluated.