The origin of ferromagnetism in d0 semiconductors is studied using first-principles methods with ZnO as a prototype material. We show that the presence of spontaneous magnetization in nitrides and oxides with sufficient holes is an intrinsic property of these first-row d0 semiconductors and can be attributed to the localized nature of the 2p states of O and N. We find that acceptor doping, especially doping at the anion site, can enhance the ferromagnetism with much smaller threshold hole concentrations. The quantum confinement effect also reduces the critical hole concentration to induce ferromagnetism in ZnO nanowires. The characteristic nonmonotonic spin couplings in these systems are explained in terms of the band coupling model.
Haowei Peng,1 H. J. Xiang,2 Su-Huai Wei,2 Shu-Shen Li,1 Jian-Bai Xia,1 and Jingbo Li1
1State Key Laboratory for Superlattices and Microstructures, Institute of Semiconductors, Chinese Academy of Sciences, P. O. Box 912, Beijing 100083, People's Republic of China
2National Renewable Energy Laboratory, Golden, Colorado 80401
Phys. Rev. Lett. 102, 017201 (2009) [4 pages]
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