Investigation of magnetic properties induced by group-V element in doped ZnO

For the potential applications in spintronics, we examine systematically the electronic properties of group-V elements (X) doped ZnO to investigate the magnetic properties induced by X based on density functional theory calculations. Our results indicates that X atoms doped in the form of a substitutional X atom at an O anion site (X-O) and at a Zn cation site combining with two Zn vacancies (X-Zn-2V(Zn) complex) under different circumstances can introduce magnetism. The magnetism comes from the p-p and p-d coupling interaction between the dopant X-p orbitals and the host O-2p and Zn-3d orbitals. The stability of the ferromagnetism (FM) phase induced by X-O defects decreases with the increase of dopant atomic number due to the lower electronegativity value, which can be interpreted by the phenomenological band-coupling model. The origin of the magnetism induced by X-Zn-2V(Zn) is similar to that of the Zn vacancy (V-Zn) in ZnO and comes from the O-2p orbitals dominantly. The FM stability introduced by X-Zn-2V(Zn) decreases with the order N < Sb < As < P, which is ascribed to the delocalization of the O-2p orbitals. The results mean that 3p/4p/5p dopants could also make ZnO materials into diluted magnetic semiconductors.