Nitrogen Vacancy and Magnetic Property in Cu-Doped AlN From First-Principles Calculations

The effects on the ferromagnetism of a nitrogen defect in Cu-doped AlN with a Cu concentration of 2.77-8.33% have been investigated by first-principles. For Al0.9723Cu0.0277N, a global magnetic moment of 1.46 mu(B)/cell, with a localized magnetic moment of 0.75 mu(B)/Cu is found. The formation of Cu-Cu in AlN with the N vacancy (V-N) is more energetically favorable than that without the V-N. Hence, the Cu + V-N state is produced easily. The Cu magnetic moment of Cu-Cu pair becomes very low by the weak 3d-3d spin coupling due to the spin-exchange interaction between Cu-3d and N defect states.