Direct observation of chiral edge current at zero magnetic field in a magnetic topological insulator
The chiral edge current is the boundary manifestation of the Chern number of a quantum anomalous Hall (QAH) insulator. The van der Waals antiferromagnet MnBi<sub>2</sub>Te<sub>4</sub> 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.
Authors
- Hongxu Yao
- Yishi Lin (ORCID: https://orcid.org/0000-0002-6124-1137)
- Qiushi He
- Zichen Lian (ORCID: https://orcid.org/0009-0006-9445-6704)
- Weiyan Lin
- Xiaodong Zhou (ORCID: https://orcid.org/0000-0002-5602-1084)
- Yang Wu (ORCID: https://orcid.org/0000-0002-0460-3621)
- Yihua Wang (ORCID: https://orcid.org/0000-0002-5590-5881)
- Yang Feng (ORCID: https://orcid.org/0000-0002-3584-1227)
- Jian Shen (ORCID: https://orcid.org/0000-0001-5670-1429)
- Youfang Wang
- Hao Li (ORCID: https://orcid.org/0000-0002-9294-9103)
- Chang Liu
- Jinsong Zhang (ORCID: https://orcid.org/0000-0002-3601-4995)
- Jing Wang (ORCID: https://orcid.org/0000-0002-4674-9485)
- Yongchao Wang (ORCID: https://orcid.org/0000-0002-1869-2290)
- Yongqian Wang (ORCID: https://orcid.org/0000-0003-3377-3336)
- Shuai Yang (ORCID: https://orcid.org/0000-0001-9798-2239)
- Yayu Wang (ORCID: https://orcid.org/0000-0003-2330-1642)
- Jinjiang Zhu
Institutions
- Fudan University (CN)
- Hefei University (CN)
- Foxconn (China) (CN)
- ShangHai JiAi Genetics & IVF Institute (CN)
- Collaborative Innovation Center of Advanced Microstructures (CN)
- Beijing Academy of Quantum Information Sciences (CN)
- State Key Laboratory of Surface Physics
- Beijing University of Chemical Technology (CN)
- Renmin University of China (CN)
- Tsinghua University (CN)
Publication Details
- Journal
- Nature Communications
- Published
- 2025-01-22
- DOI
- https://doi.org/10.1038/s41467-025-56326-7
- Citations
- 3
- Primary Topic
- Topological Materials and Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 3.74
Funders
- National Natural Science Foundation of China
- China Postdoctoral Science Foundation
- Science and Technology Commission of Shanghai Municipality
- National Postdoctoral Program for Innovative Talents