Spin scattering and noncollinear spin structure-induced intrinsic anomalous Hall effect in antiferromagnetic topological insulator MnBi2Te4
Spin scattering and noncollinear spin structure-induced intrinsic anomalous Hall effect in antiferromagnetic topological insulator MnBi2Te4
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DOI：
10.1103/physrevresearch.1.012011
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发表时间：
2019-08-19
影响因子：
4.2
通讯作者：
Mao, Zhiqiang
中科院分区：
文献类型：
--
作者：
Lee, Seng Huat;Zhu, Yanglin;Mao, Zhiqiang
MnBi_2Te_4是一种内禀反铁磁拓扑绝缘体，是产生量子反常霍尔绝缘体和轴子绝缘体态的理想平台。我们对这种材料的结构、非平凡表面态和磁输运性质进行了全面的研究。我们的结果揭示了一个内在的反常霍尔效应所产生的非共线自旋结构的磁场平行于c轴。我们观察到的负磁阻在任意磁场方向低于和高于尼尔温度（TN），提供了明确的证据，强自旋涨落驱动的自旋散射在AFM和顺磁状态。此外，我们发现，非平凡的表面状态打开一个大的差距（类似于85 meV），甚至远高于TN。我们的研究结果表明，体能带结构的MnBi_2Te_4是强烈耦合的磁性和一个净Berry曲率的动量空间中可以创建在倾斜的AFM状态。此外，我们的研究结果表明，表面态的差距开口是内在的，可能是由这种材料中的强自旋波动引起的。
MnBi2Te4 has recently been established as an intrinsic antiferromagnetic (AFM) topological insulator-an ideal platform to create quantum anomalous Hall insulator and axion insulator states. We performed comprehensive studies on the structure, nontrivial surface state, and magnetotransport properties of this material. Our results reveal an intrinsic anomalous Hall effect arising from a noncollinear spin structure for the magnetic field parallel to the c axis. We observed negative magnetoresistance under arbitrary field orientation below and above the Neel temperature (T-N), providing clear evidence for strong spin fluctuation-driven spin scattering in both the AFM and paramagnetic states. Furthermore, we found that the nontrivial surface state opens a large gap (similar to 85 meV) even far above T-N. Our findings demonstrate that the bulk band structure of MnBi2Te4 is strongly coupled with the magnetic property and that a net Berry curvature in momentum space can be created in the canted AFM state. In addition, our results imply that the gap opening in the surface states is intrinsic, likely caused by the strong spin fluctuations in this material.