Density Functional Theory‐based Investigation of Terbium Aluminum Garnet Tb ₃ Al ₅ O ₁₂ for Advanced Thermal Barrier Applications

ABSTRACT The exceptional thermal stability, low thermal conductivity, and mechanical robustness of terbium aluminum oxide, known as Terbium Aluminum Garnet (TAG), have made it a viable candidate for next‐generation thermal barrier coating (TBC) applications. To address this gap, we explore the structural, electronic, mechanical, optical, and thermodynamic properties of TAG through density functional theory‐based simulation. The result reveals that TAG compound exhibits excellent thermodynamic, thermal, and structural stability under various conditions. The electronic and optical properties were computed utilizing the Tran‐Blaha modified Becke‐Johnson potential, indicating that the TAG compound exhibits insulating characteristics, resulting in low electrical conductivity and high thermal resistance. The calculated elastic constants meet the Born criterion for mechanical stability, and the high values ​​of bulk and shear moduli indicate that the mechanical strength and stiffness of the material are excellent. These findings highlight TAG compound as a potential candidate for advanced TBC applications, photoluminescence, and photochromism, achieving structural stability, mechanical strength, and exceptional thermal performance under extreme conditions.