Direct observation of chiral edge current at zero magnetic field in a magnetic topological insulator

Jinjiang Zhu; Yang Feng; Xiaodong Zhou; Yongchao Wang; Hongxu Yao; Zichen Lian; Weiyan Lin; Qiushi He; Yishi Lin; Youfang Wang; Yongqian Wang; Shuai Yang; Hao Li; Yang Wu; Chang Liu; Jing Wang; Jian Shen; Jinsong Zhang; Yayu Wang; Yihua Wang

doi:10.1038/s41467-025-56326-7

Direct observation of chiral edge current at zero magnetic field in a magnetic topological insulator

Nat Commun. 2025 Jan 23;16(1):963. doi: 10.1038/s41467-025-56326-7.

Authors

Jinjiang Zhu^#¹, Yang Feng^#², Xiaodong Zhou^#^{3

4

5}, Yongchao Wang^#⁶, Hongxu Yao¹, Zichen Lian⁷, Weiyan Lin^{1

3}, Qiushi He¹, Yishi Lin¹, Youfang Wang¹, Yongqian Wang^{8

9}, Shuai Yang^{8

9}, Hao Li^{10

11}, Yang Wu^{11

12}, Chang Liu^{8

9}, Jing Wang¹, Jian Shen^{1

3

4

5

13

14}, Jinsong Zhang^{15

16

17}, Yayu Wang^{7

18

19}, Yihua Wang^{20

21}

Affiliations

¹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
² Beijing Academy of Quantum Information Sciences, Beijing, PR China.
³ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, China.
⁴ Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai, China.
⁵ Shanghai Qi Zhi Institute, Shanghai, China.
⁶ Beijing Innovation Center for Future Chips, Tsinghua University, Beijing, PR China.
⁷ State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, PR China.
⁸ Beijing Key Laboratory of Opto-electronic Functional Materials & Micro-Nano Devices, Department of Physics, Renmin University of China, Beijing, China.
⁹ Key Laboratory of Quantum State Construction and Manipulation (Ministry of Education), Renmin University of China, Beijing, China.
¹⁰ School of Materials Science and Engineering, Tsinghua University, Beijing, PR China.
¹¹ Tsinghua-Foxconn Nanotechnology Research Center, Department of Physics, Tsinghua University, Beijing, PR China.
¹² College of Math and Physics, Beijing University of Chemical Technology, Beijing, PR China.
¹³ Collaborative Innovation Center of Advanced Microstructures, Nanjing, China.
¹⁴ Shanghai Research Center for Quantum Sciences, Shanghai, China.
¹⁵ State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, PR China. [email protected].
¹⁶ Frontier Science Center for Quantum Information, Beijing, PR China. [email protected].
¹⁷ Hefei National Laboratory, Hefei, PR China. [email protected].
¹⁸ Frontier Science Center for Quantum Information, Beijing, PR China.
¹⁹ Hefei National Laboratory, Hefei, PR China.
²⁰ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China. [email protected].
²¹ Shanghai Research Center for Quantum Sciences, Shanghai, China. [email protected].

^# Contributed equally.

PMID: 39843540
DOI: 10.1038/s41467-025-56326-7

Abstract

The chiral edge current is the boundary manifestation of the Chern number of a quantum anomalous Hall (QAH) insulator. The van der Waals antiferromagnet MnBi₂Te₄ is theorized to be a QAH in odd-layers but has shown Hall resistivity below the quantization value at zero magnetic field. Here, we perform scanning superconducting quantum interference device (sSQUID) microscopy on these seemingly failed QAH insulators to image their current distribution. When gated to the charge neutral point, our device exhibits edge current, which flows unidirectionally on the odd-layer boundary both with vacuum and with the even-layers. The edge current chirality reverses with the magnetization of the bulk. Surprisingly, we find the edge channels coexist with finite bulk conduction even though the bulk chemical potential is in the band gap, suggesting their robustness under significant edge-bulk scattering. Our result establishes the existence of chiral edge currents in a topological antiferromagnet and offers an alternative for identifying QAH states.

Abstract

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