First-principles calculations to investigate structural, elastic, electronic and thermodynamic properties of monoclinic GaN ₅ under high pressure

As a nitrogen-rich compound and a high-energy density material, the physical properties (mechanical, electronic, vibrational, energetic and thermodynamic properties) of GaN 5 under pressure have not been sufficiently investigated. This paper adopts the first-principles calculations method based on density functional theory to calculate the physical properties of GaN 5 under high pressure. The results show that within 85-135 GPa, the GaN 5 structure exhibits both dynamic and mechanical stability. With the increasing pressure, the Young’s modulus, bulk modulus and shear modulus are all increased. And the material’s ductility and the covalent bonds between N atoms are significantly enhanced. GaN 5 is an indirect semiconductor, and its band gap decreases with increasing pressure. Finally, the energy density is used to estimate its detonation pressure and GaN 5 also displays distinctive thermodynamic characteristics.