First-principles prediction of the structural and electronic properties of GaxY1−xN compounds

In this work, we have carried out a first-principles study of the structural stability and the electronic properties of the GaxY1−xN ternary compound (with x = 0, 0.25, 0.50, 0.75 and 1.0) in the rock-salt and wurtzite like structures. Total energy calculations were performed using the density functional theory (DFT) within the full-potential linearized augmented plane wave (FP-LAPW) method. To represent the electronic exchange and correlation effects, we have used the generalized gradient approximation (GGA) and the modified Becke–Johonson (MBJ) potential. We have also observed that for gallium concentrations less than 35%, the most favorable structure was the rock-salt-like structure. Beyond 35% of gallium, the most stable structure is the wurtzite-like structure. We have observed that the incorporation of gallium atoms plays a crucial role in changing the value of the gap and its type from indirect to direct.