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.
@article{arxiv.2507.03342,
title = {Quantized Topological States and Parity Anomaly in Intrinsic Quantum Anomalous Hall Insulator MnBi2Te4},
author = {Zhongxun Guo and Jingjing Gao and Zhiwei Huang and Di Yue and Zhaochen Liu and Mingyan Luo and Shuang Wu and Xinyu Chen and Guangyi Huang and Yujun Deng and Mengzhu Shi and Yin Xia and Zihan Xu and Chuanying Xi and Guangli Kuang and Changlin Zheng and Shiwei Wu and Hua Jiang and X. C. Xie and Wenzhong Bao and Yuping Sun and Xian Hui Chen and Jing Wang and Wei Ruan and Yuanbo Zhang},
journal= {arXiv preprint arXiv:2507.03342},
year = {2025}
}