Xu Runzhe, Bai Yunhe, Zhou Jingsong, Li Jiaheng, Gu Xu, Qin Na, Yin Zhongxu, Du Xian, Zhang Qinqin, Zhao Wenxuan, Li Yidian, Wu Yang, Ding Cui, Wang Lili, Liang Aiji, Liu Zhongkai, Xu Yong, Feng Xiao, He Ke, Chen Yulin, Yang Lexian
State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China.
Beijing Academy of Quantum Information Sciences, Beijing 100193, China.
Nano Lett. 2022 Aug 10;22(15):6320-6327. doi: 10.1021/acs.nanolett.2c02034. Epub 2022 Jul 27.
Ultrathin films of intrinsic magnetic topological insulator MnBiTe exhibit fascinating quantum properties such as the quantum anomalous Hall effect and the axion insulator state. In this work, we systematically investigate the evolution of the electronic structure of MnBiTe thin films. With increasing film thickness, the electronic structure changes from an insulator type with a large energy gap to one with in-gap topological surface states, which is, however, still in drastic contrast to the bulk material. By surface doping of alkali-metal atoms, a Rashba split band gradually emerges and hybridizes with topological surface states, which not only reconciles the puzzling difference between the electronic structures of the bulk and thin-film MnBiTe but also provides an interesting platform to establish Rashba ferromagnet that is attractive for (quantum) anomalous Hall effect. Our results provide important insights into the understanding and engineering of the intriguing quantum properties of MnBiTe thin films.
本征磁性拓扑绝缘体MnBiTe的超薄膜展现出迷人的量子特性，如量子反常霍尔效应和轴子绝缘体态。在这项工作中，我们系统地研究了MnBiTe薄膜电子结构的演变。随着薄膜厚度的增加，电子结构从具有大能隙的绝缘体类型转变为具有带内拓扑表面态的类型，然而，这仍然与块体材料形成鲜明对比。通过碱金属原子的表面掺杂，一个Rashba分裂带逐渐出现并与拓扑表面态杂化，这不仅调和了块体和薄膜MnBiTe电子结构之间令人困惑的差异，还提供了一个建立对（量子）反常霍尔效应有吸引力的Rashba铁磁体的有趣平台。我们的结果为理解和调控MnBiTe薄膜引人入胜的量子特性提供了重要见解。
