Pan Lei, Liu Xiaoyang, He Qing Lin, Stern Alexander, Yin Gen, Che Xiaoyu, Shao Qiming, Zhang Peng, Deng Peng, Yang Chao-Yao, Casas Brian, Choi Eun Sang, Xia Jing, Kou Xufeng, Wang Kang L
Department of Electrical and Computer Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA.
School of Information Science and Technology, ShanghaiTech University, Shanghai 200031, China.
Sci Adv. 2020 Jun 17;6(25):eaaz3595. doi: 10.1126/sciadv.aaz3595. eCollection 2020 Jun.
Quantum anomalous Hall effect has been observed in magnetically doped topological insulators. However, full quantization, up until now, is limited within the sub-1 K temperature regime, although the material's magnetic ordering temperature can go beyond 100 K. Here, we study the temperature limiting factors of the effect in Cr-doped (BiSb)Te systems using both transport and magneto-optical methods. By deliberate control of the thin-film thickness and doping profile, we revealed that the low occurring temperature of quantum anomalous Hall effect in current material system is a combined result of weak ferromagnetism and trivial band involvement. Our findings may provide important insights into the search for high-temperature quantum anomalous Hall insulator and other topologically related phenomena.
在磁性掺杂的拓扑绝缘体中已观测到量子反常霍尔效应。然而，迄今为止，尽管材料的磁有序温度可超过100 K，但完整的量子化仅局限于低于1 K的温度范围。在此，我们使用输运和磁光方法研究了Cr掺杂（BiSb）Te体系中该效应的温度限制因素。通过精心控制薄膜厚度和掺杂分布，我们发现当前材料体系中量子反常霍尔效应出现温度较低是弱铁磁性和平凡能带参与的综合结果。我们的研究结果可能为寻找高温量子反常霍尔绝缘体及其他拓扑相关现象提供重要见解。
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