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 (XO) and at a Zn cation site combining with two Zn vacancies (XZn-2VZn 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 XO 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 XZn-2VZn is similar to that of the Zn vacancy (VZn) in ZnO and comes from the O-2p orbitals dominantly. The FM stability introduced by XZn-2VZn 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.