First-principles density functional theory was employed to systematically study the effects of pressure on the crystal structure, elastic properties, and electronic characteristics of Al₄In₂N₆. The lattice constants of Al₄In₂N₆ decrease with increasing pressure, exhibiting anisotropic compression with greater compressibility along the c-axis. In terms of mechanical properties, the bulk modulus increases with pressure, indicating enhanced compressive resistance. Notably, the Vickers hardness decreases with increasing pressure, suggesting that high pressure could induce plastic deformation in Al₄In₂N₆. Calculations of elastic constants and phonon spectra confirm that Al₄In₂N₆ retains mechanical and dynamical stability across the 0–30 GPa pressure range.
Electronic structure calculations reveal that Al₄In₂N₆ possesses a direct band gap, with non-overlapping conduction and valence bands at the Fermi level and higher carrier mobility in the conduction band compared to the valence band. The band gap increases nearly linearly with pressure, from 3.35 eV at 0 GPa to 4.24 eV at 30 GPa, demonstrating significant pressure-induced modulation of the electronic structure. Furthermore, differential charge density analysis reveals that increasing pressure strengthens Al-N and In-N bonds in Al₄In₂N₆ through shortened interatomic distances and stronger atomic interactions, increasing its compression resistance.
In conclusion, this study not only enhances our understanding of the high-pressure properties of Al₄In₂N₆ but also provides theoretical guidance for its application in UV optoelectronics. Pressure-driven modulation of its mechanical and electronic characteristics highlights its potential for efficient high-pressure optoelectronic devices and materials.