Role of vacancy-type defects in magnetism of GaMnN

Role of vacancy-type (N vacancy (V-N) and Ga vacancy (V-Ga)) defects in magnetism of GaMnN is investigated by first-principle calculation. Theoretical results show that both the V-N and V-Ga influence the ferromagnetic state of a system. The V-N can induce antiferromagnetic state and the V-Ga indirectly modify the stability of the ferromagnetic state by depopulating the Mn levels in GaMnN. The transfer of electrons between the vacancy defects and Mn ions results in converting Mn3+ (d(4)) into Mn2+ (d(5)). The introduced V-N and the ferromagnetism become stronger and then gradually weaker with Mn concentration increasing, as well as the coexistence of Mn3+ (d(4)) and Mn2+ (d(5)) are found in GaMnN films grown by metal-organic chemical vapor deposition. The analysis suggests that a big proportion of Mn3+ changing into Mn2+ will reduce the exchange interaction and magnetic correlation of Mn atoms and lead to the reduction of ferromagnetism of material.National Natural Science Foundation of China [61204008, 11075176, 11505211]; National Key Basic Research Special Foundation of China [2013CB328705]SCI(E)EI中国科技核心期刊(ISTIC)ARTICLEzyguo@ihep.ac.cn; cuimq@ihep.ac.cn; gyzhang@pku.edu.cn6521-5262