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

IF 14.7 1区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

Nature Communications Pub Date : 2025-01-23 DOI:10.1038/s41467-025-56326-7

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

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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.

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磁拓扑绝缘体零磁场下手性边电流的直接观察

手性边缘电流是量子反常霍尔（QAH）绝缘子陈恩数的边界表现。范德华反铁磁体MnBi2Te4理论上是奇层QAH，但在零磁场下霍尔电阻率低于量子化值。在这里，我们对这些看似失效的QAH绝缘体进行扫描超导量子干涉装置（sSQUID）显微镜，以成像它们的电流分布。当门控到电荷中性点时，我们的器件显示边缘电流，该电流在真空和偶层的奇层边界上单向流动。边缘电流手性随体的磁化而反转。令人惊讶的是，我们发现边缘通道与有限体传导共存，即使体化学势在带隙中，这表明它们在显著的边缘-体散射下具有鲁棒性。我们的结果建立了拓扑反铁磁体中手性边缘电流的存在，并为识别QAH态提供了一种替代方法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Nature Communications Biological Science Disciplines-

CiteScore

24.90

自引率

2.40%

发文量

6928

审稿时长

3.7 months

期刊介绍： Nature Communications, an open-access journal, publishes high-quality research spanning all areas of the natural sciences. Papers featured in the journal showcase significant advances relevant to specialists in each respective field. With a 2-year impact factor of 16.6 (2022) and a median time of 8 days from submission to the first editorial decision, Nature Communications is committed to rapid dissemination of research findings. As a multidisciplinary journal, it welcomes contributions from biological, health, physical, chemical, Earth, social, mathematical, applied, and engineering sciences, aiming to highlight important breakthroughs within each domain.