Using the first-principles method based on the density functional theory, we investigated the ferromagnetic properties, electronic structures, and formation energies of Zn vacancy monodoping and (Zn vacancy, Li) codoped ZnO. The results indicate that both cases prefer the ferromagnetic ground state. It was found that the Zn vacancy defect brings a spin polarized state in the nearest neighbor oxygen atoms, and the magnetic moments mainly come from the 0 atoms surrounding the defect centers, which
