Role of vacancy-type（N vacancy（VN） and Ga vacancy（VGa）） defects in magnetism of GaMnN is investigated by first-principle calculation.Theoretical results show that both the VNand VGainfluence the ferromagnetic st...Role of vacancy-type（N vacancy（VN） and Ga vacancy（VGa）） defects in magnetism of GaMnN is investigated by first-principle calculation.Theoretical results show that both the VNand VGainfluence the ferromagnetic state of a system.The VNcan induce antiferromagnetic state and the VGaindirectly 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＋（d4） into Mn2＋（d5）.The introduced VNand the ferromagnetism become stronger and then gradually weaker with Mn concentration increasing,as well as the coexistence of Mn3＋（d4） and Mn2＋（d5） 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.展开更多
GaMnN/GaN multilayers and conventional GaMnN single layers are grown by metal-organic chemical vapor deposition. Both kinds of samples show room-temperature ferromagnetism. After thermal annealing, the sample with GaM...GaMnN/GaN multilayers and conventional GaMnN single layers are grown by metal-organic chemical vapor deposition. Both kinds of samples show room-temperature ferromagnetism. After thermal annealing, the sample with GaMnN/GaN multilayer structure displays a larger coercivity and better thermal stability compared to the GaMnN single layer. The annealing effects on Vca related defects are observed from photoluminescenee measurements. Moreover, a different magnetic behavior is also found in the annealed GaMnN films grown on different （n-type GaN and p-type GaN） templates. These kinds of structure-dependent magnetic behaviors indicate that defects or carriers transformation introduced during annealing may have important effects on the electronic structure of Mn ions and on the ferromagnetism. Our work may be helpful for further understanding the origin of ferromagnetism in GaN-based diluted magnetic semiconductors.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61204008,11075176,and 11505211)the National Key Basic Research Special Foundation of China(Grant No.2013CB328705)
文摘Role of vacancy-type（N vacancy（VN） and Ga vacancy（VGa）） defects in magnetism of GaMnN is investigated by first-principle calculation.Theoretical results show that both the VNand VGainfluence the ferromagnetic state of a system.The VNcan induce antiferromagnetic state and the VGaindirectly 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＋（d4） into Mn2＋（d5）.The introduced VNand the ferromagnetism become stronger and then gradually weaker with Mn concentration increasing,as well as the coexistence of Mn3＋（d4） and Mn2＋（d5） 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.
基金Supported by the National Basic Research Program of China under Grants Nos 2013CB328705 and 2011CB013101, and the National Natural Science Foundation of China under Grants Nos 61306110, 61327801, 61376012, 61204008, and 11204209.
文摘GaMnN/GaN multilayers and conventional GaMnN single layers are grown by metal-organic chemical vapor deposition. Both kinds of samples show room-temperature ferromagnetism. After thermal annealing, the sample with GaMnN/GaN multilayer structure displays a larger coercivity and better thermal stability compared to the GaMnN single layer. The annealing effects on Vca related defects are observed from photoluminescenee measurements. Moreover, a different magnetic behavior is also found in the annealed GaMnN films grown on different （n-type GaN and p-type GaN） templates. These kinds of structure-dependent magnetic behaviors indicate that defects or carriers transformation introduced during annealing may have important effects on the electronic structure of Mn ions and on the ferromagnetism. Our work may be helpful for further understanding the origin of ferromagnetism in GaN-based diluted magnetic semiconductors.
