DFT-Based Exploration of Structural, Electronic, and Metallic Characteristics of Cs₂TiXBr₆ (X = Ba, Mg, Sr) Double Perovskites

This study presents a density functional theory (DFT)–based exploration of the structural, electronic, and metallic characteristics of the double perovskite compounds Cs₂TiXBr₆ (X = Ba, Mg, Sr). Using full-potential linearized augmented plane-wave (FP-LAPW) methods within the generalized gradient approximation (GGA), the equilibrium lattice parameters, formation energies, and mechanical stability were systematically examined. The optimized structures reveal high thermodynamic and mechanical stability, confirming the feasibility of their synthesis. The electronic band structures and density of states indicate metallic behavior across all compositions, mainly arising from Ti-3d and halogen-p orbitals near the Fermi level. The metallic nature suggests strong potential for these compounds as conductive or protective coating materials. Further, the calculated elastic constants satisfy Born stability criteria, while the high bulk modulus values indicate their mechanical robustness. The findings highlight Cs₂TiXBr₆ double perovskites as promising, stable metallic systems suitable for functional surface applications and advanced coating technologies.