Shallow donor levels enhanced ferromagnetism in the In₂O₃:Co nanocrystal

¹ School of Physics and Microelectronic and Key Lab for Micro-Nano Physics and Technology of Hunan Province, Hunan University - Changsha 410082, China
² Departments of Physics and Electronics, Hengyang Normal University - Hengyang 421008, China

^a lmtang@hnu.edu.cn
^b llwang@hnu.edu.cn
^c keqiuchen@hnu.edu.cn

Received: 19 July 2011
Accepted: 30 January 2012

Abstract

Based on density functional theory calculations, we have studied the electronic structures and magnetic properties of the passivated In₂O₃:Co nanocrystal (PICN). The results show that the cobalt 3d states localize in the band gap in neutral PICN without magnetic moment. If adding an electron into the PICN, there shows about 1 μ_B magnetic moment. Interestingly, though a tin dopant only provides an additional electron, the total magnetic moment becomes 2.98 μ_B rather than 1 μ_B in a Sn-doped PICN. The increase of the magnetic moment can be explained well by the levels' coupling model.