Abstract: This article employed a first-principles calculation method based on density functional theory to optimize the geometric structure of the ternary layered nitride M₂AlN (M=Ti, Zr). The structural, mechanical, electronic and optical properties of the ternary layered nitride M₂AlN (M=Ti, Zr) under high pressure were investigated. The study of structural and mechanical properties reveal that Ti₂AlN exhibits superior compressibility compared to Zr₂AlN. The elastic constants further validate its mechanical stability under high pressure. Ductility and elastic anisotropy enhance under increasing pressure, with Zr₂AlN demonstrating heightened sensitivity to these pressure conditions. Research on electronic properties reveals that both ternary layered nitrides exhibit metallic behavior, and their covalent character strengthen with increasing pressure. Investigations into the optical properties reveal that the polycrystalline nature and static dielectric functions ε₁(0), along with the static refractive index n(0) of Ti₂AlN and Zr₂AlN along various axes, demonstrate relatively low anisotropy in their optical characteristics. Both ternary nitrides exhibit pronounced capabilities for light absorption and reflectivity. Theoretical inquiries in this study clarified the relevant characteristics of the ternary layered nitrides Ti₂AlN and Zr₂AlN under the elevated pressure, establishing a robust theoretical framework for subsequent experimental investigations.

Key words: Ti₂AlN and Zr₂AlN, density functional theory, first principle, mechanical property, electronics structure, optical property