Zhu Jinjiang, Feng Yang, Zhou Xiaodong, Wang Yongchao, Yao Hongxu, Lian Zichen, Lin Weiyan, He Qiushi, Lin Yishi, Wang Youfang, Wang Yongqian, Yang Shuai, Li Hao, Wu Yang, Liu Chang, Wang Jing, Shen Jian, Zhang Jinsong, Wang Yayu, Wang Yihua
State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, China.
Beijing Academy of Quantum Information Sciences, Beijing, PR China.
Nat Commun. 2025 Jan 23;16(1):963. doi: 10.1038/s41467-025-56326-7.
The chiral edge current is the boundary manifestation of the Chern number of a quantum anomalous Hall (QAH) insulator. The van der Waals antiferromagnet MnBiTe 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.
手性边缘电流是量子反常霍尔（QAH）绝缘体陈数的边界表现。理论上，范德华反铁磁体MnBiTe在奇数层时是一种QAH绝缘体，但在零磁场下其霍尔电阻率低于量子化值。在此，我们对这些看似失败的QAH绝缘体进行扫描超导量子干涉装置（sSQUID）显微镜成像，以获取其电流分布。当栅极电压调至电荷中性点时，我们的器件会出现边缘电流，该电流在奇数层与真空以及偶数层的边界上单向流动。边缘电流的手性会随着体材料的磁化而反转。令人惊讶的是，我们发现即使体材料的化学势处于带隙中，边缘通道仍与有限的体传导共存，这表明它们在显著的边缘 - 体散射下具有鲁棒性。我们的结果证实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。
