Structural stability and electronic structure of iron adsorption on the GaN(0Â 0Â 0Â 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.