Abstract Recent experiments have shown that Fe doping to the SnO2 system can increase the magnetic moment and induce a remarkable red shift of the absorption spectrum. However, the valence state of Fe is not strictly controlled in the experiment, and the relationships between the magneto-optical properties and the Fe valence state are lacking. Therefore, the electronic structures and magneto-optical properties of pure SnO2 and Fe2+/3+-doped SnO2 systems were theoretically studied. First-principles calculations revealed that Fe2+/3+ doping significantly redshifts the absorption spectral, induces spin-polarized impurity bands near the Fermi level, and leads to evident spin polarization phenomenon. Fe2+ and Fe3+ exhibit different effects on the electronic structures and magneto-optical properties of the doped system. Specifically, Fe3+ doping enhances the dominant role of p–d exchange interaction and the Fe3+ doped systems are likely to obtain high Curie temperature and magnetic moment at the same doping concentration and position; moreover, the imaginary part and absorption spectrum of the dielectric function of Fe2+-doped SnO2 systems have large new peaks in the low-energy region, which are attributed to electronic transitions from the spin-polarized impurity levels to the conduction band.

中文翻译：

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Fe2+/3+掺杂SnO2电子结构和磁光特性的第一性原理研究

摘要 最近的实验表明，在 SnO2 系统中掺杂 Fe 可以增加磁矩并引起吸收光谱的显着红移。然而，实验中并未严格控制Fe的价态，缺乏磁光性质与Fe价态的关系。因此，从理论上研究了纯 SnO2 和 Fe2+/3+ 掺杂 SnO2 系统的电子结构和磁光特性。第一性原理计算表明，Fe2+/3+ 掺杂显着红移吸收光谱，在费米能级附近诱导自旋极化杂质带，并导致明显的自旋极化现象。Fe2+和Fe3+对掺杂体系的电子结构和磁光性能表现出不同的影响。具体来说，Fe3+掺杂增强了p-d交换相互作用的主导作用，Fe3+掺杂体系在相同的掺杂浓度和位置下可能获得高居里温度和磁矩；此外，Fe2+掺杂的SnO2体系的介电函数的虚部和吸收光谱在低能区有较大的新峰，这归因于从自旋极化杂质能级到导带的电子跃迁。