First‐principles analysis reveals Li ₂ Mg ₃ Ga ₃ Ti ₄ O ₁₆ ceramic stable spinel‐type structure

Abstract In this study, we report the first comprehensive ab initio investigation of the structural, elastic, electronic, magnetic, thermoelectric, thermodynamic, and optical properties of the novel ceramic compound Li 2 Mg 3 Ga 3 Ti 4 O 16 with a spinel‐type structure. The calculations were performed within the framework of density functional theory (DFT) using the FP‐LAPW method as implemented in the WIEN2k code. Structural optimization confirmed the compound's crystallographic stability in the cubic phase (space group Fd‐3 m), and the strongly negative formation enthalpy indicates excellent thermodynamic stability. Elastic property analysis demonstrates that the compound is mechanically stable, highly rigid, brittle in nature, and exhibits an almost isotropic elastic response, consistent with the typical behavior of ceramic oxides. Electronic structure analysis reveals a spin‐polarized metallic character, dominated by the Ti 3d orbitals, and a ferromagnetic ground state. Transport properties, evaluated using the semiclassical Boltzmann theory, show high and thermally stable electrical conductivity, a moderate Seebeck coefficient, and asymmetric Hall mobility, confirming the metallic behavior and the material's potential for spin‐dependent charge transport. Thermodynamic properties, assessed through the quasi‐harmonic Debye model, demonstrate remarkable structural stability up to 1000 K, a low thermal expansion coefficient, and increasing stiffness under pressure. Finally, the calculated optical properties reveal a high refractive index, strong ultraviolet dielectric response, and distinct plasmonic peaks, indicating advanced optoelectronic behavior.