Shallow donor levels enhanced ferromagnetism in the In2O3:Co nanocrystal

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 μB magnetic moment. Interestingly, though a tin dopant only provides an additional electron, the total magnetic moment becomes 2.98 μB rather than 1 μB in a Sn-doped PICN. The increase of the magnetic moment can be explained well by the levels' coupling model.