Quantized Topological States and Parity Anomaly in Intrinsic Quantum Anomalous Hall Insulator MnBi2Te4

Zhongxun Guo; Jingjing Gao; Zhiwei Huang; Di Yue; Zhaochen Liu; Mingyan Luo; Shuang Wu; Xinyu Chen; Guangyi Huang; Yujun Deng; Mengzhu Shi; Yin Xia; Zihan Xu; Chuanying Xi; Guangli Kuang; Changlin Zheng; Shiwei Wu; Hua Jiang; X. C. Xie; Wenzhong Bao; Yuping Sun; Xian Hui Chen; Jing Wang; Wei Ruan; Yuanbo Zhang

arXiv · 2507.03342

Quantized Topological States and Parity Anomaly in Intrinsic Quantum Anomalous Hall Insulator MnBi2Te4

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Abstract

When thinned down to just a few atomic layers, the layered magnetic topological insulator MnBi2Te4 offers an exceptional platform for exploring a wide range of topological phenomena. In this work, we overcome longstanding challenges in synthesizing high-purity MnBi2Te4 crystals and report the observation of a myriad of quantized topological states in high-quality five-septuple-layer (5-SL) samples under magnetic fields up to 45 Tesla. We show that the nontrivial topology of 5-SL MnBi2Te4, in the presence of Landau quantization, is governed by a generalized topological index rooted in the parity anomaly of Dirac fermions in (2+1) dimensions. The anomaly manifests as an anomalous Landau level, giving rise to gate-tunable helical edge transport. Our results establish high-quality MnBi2Te4 as a robust platform for exploring emergent topological states and for advancing novel quantum device applications.

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Zhongxun Guo, Jingjing Gao, Zhiwei Huang, Di Yue, Zhaochen Liu, Mingyan Luo, Shuang Wu, Xinyu Chen, Guangyi Huang, Yujun Deng, Mengzhu Shi, Yin Xia, Zihan Xu, Chuanying Xi, Guangli Kuang, Changlin Zheng, Shiwei Wu, Hua Jiang, X. C. Xie, Wenzhong Bao, Yuping Sun, Xian Hui Chen, Jing Wang, Wei Ruan, Yuanbo Zhang. 2025-07-04. Quantized Topological States and Parity Anomaly in Intrinsic Quantum Anomalous Hall Insulator MnBi2Te4. https://arxiv.org/abs/2507.03342

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