Using first-principles calculations, an investigation was made of the electronic and magnetic properties of Zn vacancy in ZnO with and without Li-doping. It was found that the Zn vacancy could induce magnetism but the formation energy of the system was high. It was also found that the Li-dopant at either the substitutional sites or the interstitial sites and both at two sites could lower the formation energy of Zn vacancy. The total magnetic moments of the system was increased after Li doping at the substitutional site, while it was decreased after Li doping at the interstitial site. In addition, the extended tails of the wave functions of Zn vacancy made long-ranged spin couplings possible. Li atoms at the substitutional sites further stabilize the long-ranged ferromagnetism induced by Zn vacancies. Thus, it was possible to tune the magnetism of ZnO through defect engineering.

Effect of Li-Doping on the Magnetic Properties of ZnO with Zn Vacancies. Gao, H.X., Xia, J.B.: Journal of Applied Physics, 2012, 111[9], 093902