Structural stability and electronic structure of iron adsorption on the GaN(0 0 0 1) surface

► The most stable positions of a Fe adatom on GaN(0 0 0 1) surface are the H3 sites and T4 sites, for low and high Fe coverage respectively. ► The Fe–H3 surface reconstruction exhibits a half-metallic behavior with a spin band gap and stable ferromagnetism ordering. ► The iron monolayers on the GaN(0 0 0 1) surface present a ferromagnetic order and a large thermal stability. ► The iron monolayer stability may be due to the Fe–Ga covalent bond formation on the GaN(0 0 0 1) surface. In this work, we have investigated by means of first-principles spin-polarized calculations, the electronic and magnetic properties of iron (Fe) adsorption and diffusion on the GaN(0 0 0 1) surface using density functional theory (DFT) within a plane-wave pseudopotential scheme. In the surface adsorption study, results show that the most stable positions of a Fe adatom on GaN(0 0 0 1) surface are the H3 sites and T4 sites, for low and high Fe coverage respectively. We found that the Fe–H3 2 × 2 surface reconstruction exhibits a half-metallic behavior with a spin band gap and stable ferromagnetism ordering, which is a desirable property for high-efficiency magnetoelectronic devices. In addition, confirming previous experimental results, we found that the iron monolayers present a ferromagnetic order and a large thermal stability. This is interesting from a theoretical point of view and for its technological applications.