CEMES, CNRS and Université de Toulouse, Toulouse, France.
J Phys Condens Matter. 2013 Jun 26;25(25):256002. doi: 10.1088/0953-8984/25/25/256002. Epub 2013 May 30.
We used the DFT + U method to describe the modification of the physical properties induced by cationic point defects in cubic magnetite Fe3O4. We considered the case of Fe vacancies and interstitial atoms in non-stoichiometric magnetite, and of Frenkel defects in a stoichiometric crystal. For each of these defects, we give results on the modification of the magnetic moment of atoms near the defect. We describe the local reorganization of the electric charge which is responsible for changes in the average oxidation degree of Fe atoms. We show that gap states, when they exist, do not destroy the half-metallic character of magnetite. Fe defects, however, change the filling of bands crossing the Fermi level and must be mostly responsible for a decrease in the magnetization.
我们使用 DFT + U 方法来描述立方尖晶石型磁铁矿 Fe3O4 中阳离子点缺陷引起的物理性质的改性。我们考虑了非化学计量磁铁矿中 Fe 空位和间隙原子的情况，以及化学计量晶体中的弗伦克尔缺陷。对于每一种缺陷，我们都给出了缺陷附近原子磁矩变化的结果。我们描述了负责 Fe 原子平均氧化态变化的局部电荷重排。我们表明，当存在能隙态时，它们不会破坏磁铁矿的半金属特性。然而，Fe 缺陷改变了穿过费米能级的能带的填充，这必须是导致磁化强度降低的主要原因。
