Exploring the Impact of Antimony on the Structural, Phase Transition, Optoelectronic, Elastic and Thermoelectric Properties of Aluminum Nitride: A First-Principles Approach

The structural, electronic, optical, elastic, mechanical, and thermoelectric properties of AlN_1-xSbₓ (x = 0.0, 0.25, 0.50, 0.75, and 1.0) semiconductors were systematically investigated using the full-potential linearized augmented plane-wave (FP-LAPW) method within the framework of density functional theory (DFT) as implemented in the WIEN2k software. Structural parameters, including lattice constants, bulk modulus, and transition pressures, were computed using the WC-GGA functional, showing excellent agreement with experimental and theoretical data for binary compounds, while results for ternary alloys are presented as predictive insights. Elastic constants and mechanical properties such as brittleness, ductility, hardness, and acoustic behavior were derived, confirming structural integrity and anisotropic mechanical characteristics. Electronic properties were analyzed using EV–GGA, TB–mBJ, and KTB–mBJ exchange-correlation schemes, revealing wide band gap only for AlN, with indirect gaps in binary compounds (AlN, AlSb) and direct gaps in ternary alloys (AlN0.75Sb0.25, AlN0.5Sb0.5, and AlN0.25Sb0.75), highlighting their potential for optoelectronic applications. Optical properties, including the dielectric function, refractive index, and absorption coefficient, were computed using the KTB–mBJ scheme, elucidating their strong correlation with the electronic band structure. Finally, thermoelectric performance was evaluated, demonstrating promising characteristics for energy applications, thereby offering comprehensive insights into the multifunctional potential of these semiconductors.