The electronic structure and magnetic properties of In2O3 with four kinds of intrinsic point defects (O vacancy, In interstitial, O interstitial, and In vacancy) were theoretically studied using the density functional theory. The defect energy states of the O vacancy and In interstitial were close to the bottom of conduction band and acted as shallow donors, while the defect energy states of the In vacancy and O interstitial were just above the top of the valence band and acted as shallow acceptors. Without addition of any magnetic ions, all the hole states were completely spin polarized, while the electron states displayed no spin polarization. This implied that semiconducting In2O3 could display magnetic ordering, purely due to the intrinsic defects. However, the formation energies for neutral p-type defects were too high to be thermodynamically stable at reasonable temperatures. Nevertheless, it was shown that negative charging could greatly decrease the formation energies of p-type defects, simultaneously removing the local magnetic moments. It was concluded that VIn’’’ and OI’’ would be the dominant compensating defects as In2O3 was doped with transition metal ions, such as Sn, Mo, V and Cr. This result was consistent with the general view that the p-type defect was a key feature to mediate ferromagnetic coupling between transition metal ions of dilute concentration in metal oxides.

Tuning Magnetic Properties of In2O3 by Control of Intrinsic Defects. L.M.Huang, C.Arhammar, C.M.Araújo, F.Silvearv, R.Ahuja: EPL, 2010, 89[4], 47005