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Ji Y, Liu Z, Zhang P, Li L, Qi S, Chen P, Zhang Y, Yao Q, Liu Z, Wang KL, Qiao Z, Kou X. Thickness-Driven Quantum Anomalous Hall Phase Transition in Magnetic Topological Insulator Thin Films. ACS NANO 2022; 16:1134-1141. [PMID: 35005892 DOI: 10.1021/acsnano.1c08874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The quantized version of the anomalous Hall effect realized in magnetic topological insulators (MTIs) has great potential for the development of topological quantum physics and low-power electronic/spintronic applications. Here we report the thickness-tailored quantum anomalous Hall (QAH) effect in Cr-doped (Bi,Sb)2Te3 thin films by tuning the system across the two-dimensional (2D) limit. In addition to the Chern number-related QAH phase transition, we also demonstrate that the induced hybridization gap plays an indispensable role in determining the ground magnetic state of the MTIs; namely, the spontaneous magnetization owing to considerable Van Vleck spin susceptibility guarantees the zero-field QAH state with unitary scaling law in thick samples, while the quantization of the Hall conductance can only be achieved with the assistance of external magnetic fields in ultrathin films. The modulation of topology and magnetism through structural engineering may provide useful guidance for the pursuit of other QAH-based phase diagrams and functionalities.
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Affiliation(s)
- Yuchen Ji
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China 201210
- University of Chinese Academy of Sciences, Beijing, China 101408
| | - Zheng Liu
- International Center for Quantum Design of Functional Materials, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China 230026
| | - Peng Zhang
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, United States
| | - Lun Li
- University of Chinese Academy of Sciences, Beijing, China 101408
- School of Information Science and Technology, ShanghaiTech University, Shanghai, China 20031
| | - Shifei Qi
- International Center for Quantum Design of Functional Materials, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China 230026
- College of Physics, Hebei Normal University, Shijiazhuang, Hebei, China 050024
| | - Peng Chen
- University of Chinese Academy of Sciences, Beijing, China 101408
- School of Information Science and Technology, ShanghaiTech University, Shanghai, China 20031
| | - Yong Zhang
- University of Chinese Academy of Sciences, Beijing, China 101408
- School of Information Science and Technology, ShanghaiTech University, Shanghai, China 20031
| | - Qi Yao
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China 201210
| | - Zhongkai Liu
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China 201210
| | - Kang L Wang
- Department of Electrical Engineering, University of California, Los Angeles, California 90095, United States
| | - Zhenhua Qiao
- International Center for Quantum Design of Functional Materials, Hefei National Laboratory for Physical Sciences at Microscale, CAS Key Laboratory of Strongly-Coupled Quantum Matter Physics, and Department of Physics, University of Science and Technology of China, Hefei, Anhui, China 230026
| | - Xufeng Kou
- ShanghaiTech Laboratory for Topological Physics, School of Physical Science and Technology, ShanghaiTech University, Shanghai, China 201210
- School of Information Science and Technology, ShanghaiTech University, Shanghai, China 20031
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