First principle insights, Electronic, P-Dos, optical properties, and Elastic Tensor calculation of Ba2KOsO6 Triple Perovskite

Abstract

The triple perovskite Ba₂KOsO₆ has been investigated by first-principles density functional theory within the Perdew–Burke–Ernzerhof generalised gradient approximation. The compound crystallises in the cubic Fm3m space group, featuring ordered Ba, K, and Os cations within corner-sharing OsO₆ octahedra. Spin-polarised electronic band-structure calculations along the high-symmetry path W–L–Γ–X–W–K reveal an indirect band gap of 2.5 eV in the spin-up channel and 2.8 eV in the spin-down channel, confirming a robust semiconducting ground state with no states crossing the Fermi level. The projected density of states shows strong hybridisation between Os 5d and O 2p orbitals in the valence band, while the conduction band is dominated by Os 5d states; the spin asymmetry yields a net magnetic moment localised on the Os⁶⁺ sites, consistent with ferrimagnetic ordering. Optical properties derived from the complex dielectric function demonstrate pronounced absorption in the visible-to-ultraviolet range, moderate refractive index, and low reflectivity, indicating suitability for optoelectronic and magneto-optical devices. Elastic-tensor calculations confirm mechanical stability (all C_ij > 0), ductility (B/G > 1.25), and elastic anisotropy, with bulk modulus 26.33 GPa and Young’s modulus 34.94 GPa. These results establish Ba₂KOsO₆ as a promising Os-based triple perovskite for spintronic, optical, and mechanically robust applications.