Bipolar magnetic materials play an important role in spintronics. Its unique electronic structure allows the materials to easily regulate fully spin-polarized currents with different spin polarization directions by a gate voltage. It is predicted that 2D monolayer Fe₂O₃ is a new class of bipolar magnetic semiconductor (BMS) materials by first-principles calculations. The valence band (VB) and the conduction band (CB) have opposite spin polarizations near the Fermi level, and a direct band gap of 0.28 eV between the conduction band bottom (CBM) and the valence band top (VBM). At the same time, the two spin channels have relatively large spin-conserved gaps of 1.05 eV and 2.40 eV. The ground state of the Fe₂O₃ lattice is a ferromagnetic (FM) state. It has strong intrinsic spin polarization and has a magnetic moment of 10.0 ${\mu }_B$ per unit cell, and the spin polarization is mainly derived from the transition metal Fe atom. The Bader analysis find that the local magnetic moment of each Fe atom is 4.2 ${\mu }_B$, and the local magnetic moment of each O atom is only 0.5 ${\mu }_B$. The mechanism of magnetism could be understood by the direct exchange between the orbitals of Fe atom. The Curie temperature (T_C) of the Fe₂O₃ calculated based on Monte Carlo (MC) simulation up to 110 K, which is much larger than the 45 K of CrI₃. The characteristics of electrically-controlled polarization currents in bipolar magnetic semiconductor materials have broadened application prospects in the development of spintronics and the construction of bipolar magnetic electronic devices.

双极磁性材料在自旋电子学中起着重要作用。其独特的电子结构使材料可以通过栅极电压轻松调节具有不同自旋极化方向的完全自旋极化电流。通过第一性原理计算，可以预测二维单层Fe ₂ O ₃是一类新型的双极磁性半导体（BMS）材料。价带（VB）和导带（CB）在费米能级附近具有相反的自旋极化，并且导带底（CBM）和价带顶（VBM）之间的直接带隙为0.28 eV。同时，两个自旋通道具有1.05 eV和2.40 eV的相对较大的自旋保守间隙。Fe ₂ O ₃的基态晶格是铁磁（FM）状态。它具有很强的固有自旋极化，磁矩为10.0${\mu }_{乙}$每单位晶胞，并且自旋极化主要来自过渡金属Fe原子。Bader分析发现，每个Fe原子的局部磁矩为4.2${\mu }_{乙}$，每个O原子的局部磁矩仅为0.5 ${\mu }_{乙}$。磁性的机理可以通过铁原子轨道之间的直接交换来理解。居里温度（Ť _Ç的）中的Fe ₂ ö ₃基于蒙特卡罗（MC）模拟到110 K，其比值CrI的45ķ大得多计算₃。双极磁性半导体材料中电控极化电流的特性在自旋电子学的发展和双极磁性电子器件的构造中具有广阔的应用前景。