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arXiv · 2207.08371

Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators

Ling-Jie Zhou·Ruobing Mei·Yi-Fan Zhao·Ruoxi Zhang·Deyi Zhuo·Zi-Jie Yan·Wei Yuan·Morteza Kayyalha·Moses H. W. Chan·Chao-Xing Liu·Cui-Zu Chang
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Abstract

In quantum anomalous Hall (QAH) insulators, the interior is insulating but electrons can travel with zero resistance along one-dimensional conducting paths known as chiral edge channels (CECs). These CECs have been predicted to be confined to the one-dimensional (1D) edges and exponentially decay in the two-dimensional (2D) bulk. In this work, we present the results of a systematic study of QAH devices fashioned in a Hall bar geometry of different widths. At the charge neutral point, the QAH effect persists in a Hall bar device with a width of only ~72 nm, implying the intrinsic decaying length of CECs is less than ~36 nm. In the electron-doped regime, we find that the Hall resistance deviates quickly from the quantized value when the sample width is less than 1 um. Our theoretical calculations suggest that the deviation from the quantized Hall resistance in narrow QAH samples originates from the interaction between two opposite CECs mediated by disorder-induced bulk states in QAH insulators, consistent with our experimental observations.

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Ling-Jie Zhou, Ruobing Mei, Yi-Fan Zhao, Ruoxi Zhang, Deyi Zhuo, Zi-Jie Yan, Wei Yuan, Morteza Kayyalha, Moses H. W. Chan, Chao-Xing Liu, Cui-Zu Chang. 2022-07-18. Confinement-Induced Chiral Edge Channel Interaction in Quantum Anomalous Hall Insulators. https://doi.org/10.1103/physrevlett.130.086201

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