Magnetism in Ni-doped AlN with N vacancy: A first-principles study

摘要

We carried out first-principles calculations in order to provide comprehensive information regarding the nitrogen vacancy effects (N_V) on the magnetism of Ni_xAl_(1-x)N(x = 0.028) system. It has been found that the system is energetically more favorable for single Ni doping in Al site with one N-vacancy when compared to single Ni doping configuration. The present calculation reveals a stable ferromagnetism in Ni-doped wurtzite AlN with a magnetic moment of 3.00 μ_B for 2.8% of Ni doping. When Ni is substituted in Al site with N-vacancy the system becomes half-metallic. The N-vacancy induced defects also show a lower magnetic moment than 3.00 μ_B, which is in good agreement with the experimental observations. The results indicate that magnetic moment is reduced by the weak 3d-3d spin coupling due to the long range hybridization between Ni-3d and N defect states.