Correlation between magnetic domain structures and quantum anomalous Hall effect in epitaxial Mn Bi 2 Te 4 thin films

作者：Yang Shi, Yunhe Bai, Yuanzhao Li, Yan Feng, Qiang Li, Huanyu Zhang, Yang Chen, Yitian Tong, Jianli Luan, Ruixuan Liu, Pengfei Ji, Zongwei Gao, Hangwen Guo, Jinsong Zhang, Yayu Wang, Xiao Feng, Ke He, Xiaodong Zhou, Jian Shen · 发表于：Physical Review Materials · 年份：2024 · DOI：10.1103/physrevmaterials.8.124202 · 被引用次数：10 · 研究领域：Magnetic and transport properties of perovskites and related materials、Topological Materials and Phenomena、Rare-earth and actinide compounds

We use magnetic force microscopy to study spatial uniformity of magnetization of epitaxially grown $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ thin films. Compared to films which exhibit no quantum anomalous Hall (QAH) effect, films with QAH effect are observed to have more spatial uniformity of magnetization with larger domain size. The domain evolution upon magnetic field sweeping indicates that the magnetic domains or the spatial nonuniformity of magnetization originate from the strong pinning of the inherent sample inhomogeneity. A direct correlation between the Hall resistivity ${\ensuremath{\rho}}_{yx}$ and the domain size has been established by analyzing a series of thin films with and without QAH effect. Our observation shows that one has to suppress the spatial nonuniformity of magnetization to allow the Hall resistivity ${\ensuremath{\rho}}_{yx}$ to be quantized. The fact that a sizable longitudinal resistivity ${\ensuremath{\rho}}_{xx}$ remains even for the QAH sample suggests a quantized Hall insulator scenario. Our work provides important insights to the understanding of the quantization mechanism and the dissipation of the QAH state in $\mathrm{Mn}{\mathrm{Bi}}_{2}{\mathrm{Te}}_{4}$ system.