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 1.46μB/cell, with a localized magnetic moment of 0.75μB/Cu is found. The formation of Cu-Cu in AlN with the N vacancy( VN)is more energetically favorable than that without theVN. Hence, theCu+ VNstate 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.