Structural and electronic properties of RuN/GaN superlattices: a first-principles study

Abstract

In this work, we investigate the structural and electronic properties of RuN/GaN superlattices, using first-principles calculations within density functional theory (DFT) and generalized gradient approximation (GGA). We have employed the full potential linearized augmented plane waves (FP-LAPW) method as implemented in the \verb"WIEN2k" code. The 1$\times$1, 1$\times$2, 1$\times$3 and 1$\times$4 RuN/GaN superlattices are studied in the wurtzite phase, which is the most stable structure of the GaN. In order to determine the best parameters, we have optimized the total energy as a function of: (i) the unit cell volume, (ii) the $c/a$ ratio and (iii) the $z$-coordinate of Ga and Ru atoms. Lattices constant, bulk moduli, cohesive and formation energies are reported as a function of the period for each RuN/GaN superlattices, and trends are discussed. On the other hand, a study of the density of states show that the superlattices present a metallic behavior. The results suggest that the RuN/GaN superlattices can be used as compounds for the fabrication of semiconductor-metal-semiconductor or semiconductor-metal devices.