The effect of pressure on the physical properties of Cu₃N

The structural, optical and electronic properties of the copper nitride (Cu₃N) bulk structure under pressure have been studied by performing accurate total energy calculations in the framework of density functional theory using the full-potential linearized augmented plane wave method. Perdew–Burke–Ernzerhof and modified Becke–Johnson parameterizations of the generalized gradient approximation were employed to obtain the structural and electronic properties of Cu₃N. The most stable crystal structure of the Cu₃N compound was found to be cubic anti-ReO₃ at ambient pressure. Moreover, the calculation of the enthalpy of different crystal structures of Cu₃N for different pressures indicates that the anti-ReO₃ cubic phase undergoes a structural phase transition for pressures higher than 30 GPa. The study of the elastic constants of the anti-ReO₃ cubic phase confirms that Cu₃N is mechanically stable under hydrostatic pressures up to 30 GPa. Moreover, with the application of pressure, the C₄₄ elastic constant, shear module and Debye temperature deviate from linear behavior at 10 GPa. An electronic study shows that there is an electronic-type phase transition from semiconductor to metal between 5 and 10 GPa and metal to semi-metal between 20 and 30 GPa applied pressures. Cu₃N is an indirect band gap semiconductor with a value of 0.56 eV. (paper)