Regulated the ferromagnetism of In[formula omitted]O[formula omitted] quantum dots by non-stoichiometry compositions

Abstract

Due to different versions of ferromagnetic origin, the magnetic properties of oxide diluted magnetic semiconductor (ODMS) cannot be accurately determined. We have systematically investigate the magnetic properties and electronic structure of In2O3 quantum dots (Qds) with non-stoichiometry ratio by first-principle method with band-structure calculations. For the sake of contrastive analysis, some models are proposed to passivate the surface dangling bonds by pseudo-hydrogen atoms. We find that: (i), dangling bonds of oxygen atoms on the surface of Qds can induce 6 μB magnetic moments due to imbalanced chemical proportion. Spin polarization energy of the structure is as low as −763 eV. (ii), internal cation vacancy can induce magnetic moment, while internal anionic vacancy or surface hanging bond passivated by pseudo-hydrogen atoms cannot produce magnetic moment; and (iii), it has broken the chemical balance ratio of doping cobalt atoms where the magnetic moment mainly local area in the cobalt atoms and a little are distributed on some special O atoms which binding with the Co atoms. All three kinds of above results indicate that the non-stoichiometry compositions play an special roles to effect the magnetic properties and electronic structure in In2O3 Qds.