First-principles prediction of the structural and electronic properties of GaxYl-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. (C) 2014 Elsevier B.V. All rights reserved.