First-principles study of Al-doped and vacancy on the magnetism of ZnO

There is a controversy over the magnetic source and mechanism of the coexistence of Al-doping and Zn vacancy or Al doping and O vacancy in ZnO systems. In order to solve the problem, the combined influence mechanism of Al doping and Zn vacancy or Al doping and O vacancy on magnetism of ZnO is studied by using the first-principle calculation in this work. The coexistence of Al doping and Zn vacancy can achieve Curie temperature higher than room temperature. Moreover, the magnetism of the doping system of Al doping and Zn vacancy is mainly contributed by electron exchange interaction through O 2p and Zn 4s states near the Zn vacancy through taking carrier as medium. However, the system of Al doping and O vacancy is non-magnetic. Meantime, in the coexistence of Al doping and Zn vacancy or O vacancy, a close relative distance between doping and vacancy will reduce the formation energy of the doping system, increase the easiness of accomplishment of doping and vacancy, and enhance the stability of the doping system.