A DFT study on physical properties of III–V compounds (AlN, GaN, AlP, and GaP) in the P3121 phase

Abstract

In this work, four III-V compounds in the P3121 phase are proposed. Based on density functional theory (DFT), their structures, stability, and mechanical, anisotropic, electronic and optical properties were investigated in detail. P3121-AlN/GaN/AlP/GaP are all proven to have dynamic and mechanical stability based on their elastic constants and phonon spectra. The calculated Vickers hardness shows that P3121-AlN and P3121-GaN possess high hardness values of 18.7 GPa and 18.1 GPa, respectively. The anisotropic properties reveal that all these materials exhibit obvious elastic anisotropy. In the P3121 phase, AlN, GaN, and GaP are direct semiconductor materials, whereas AlP is an indirect semiconductor material, with calculated energy bandgaps of 4.51 eV (P3121-AlN), 2.36 eV (P3121-GaN), 1.84 eV (P3121-GaP), and 2.01 eV (P3121-AlP). In addition, P3121-AlP has high photoelectron absorption. The calculated energy bandgaps and mechanical and optical properties suggest that P3121-AlN/GaN/AlP/GaP may possess great potential to become high-performance materials in the electronics manufacturing industry.