论文标题
在固有磁性绝缘体中，可视化纳米级的dirac质量间隙和磁性的相互作用
Visualizing the interplay of Dirac mass gap and magnetism at nanoscale in intrinsic magnetic topological insulators
论文作者
论文摘要
在固有的磁性拓扑绝缘子中，狄拉克表面状态间隙是量子异常和轴突绝缘状态的先决条件。但是，这些差距的明确实验识别已被证明是一个挑战。在这里，我们使用分子束外延来生长内在的MNBI2TE4薄膜。使用扫描隧道显微镜/光谱法，我们直接可视化Dirac质量间隙及其在磁性温度下方和高于磁性阶温度之上的消失。我们进一步揭示了狄拉克质量间隙和局部磁缺陷的相互作用。我们发现，在高缺陷区域，狄拉克质量差距崩溃。从头算和耦合的狄拉克锥模型计算提供了对缺陷密度和空间间隙变化之间相关性的显微镜起源的洞察力。这项工作提供了MNBI2TE4中狄拉克质量差距的明确识别，并通过揭示其间隙变化的显微镜起源，建立了一种材料设计原理，以实现内在磁性绝缘体中的外来状态。
In intrinsic magnetic topological insulators, Dirac surface state gaps are prerequisites for quantum anomalous Hall and axion insulating states. Unambiguous experimental identification of these gaps has proved to be a challenge, however. Here we use molecular beam epitaxy to grow intrinsic MnBi2Te4 thin films. Using scanning tunneling microscopy/spectroscopy, we directly visualize the Dirac mass gap and its disappearance below and above the magnetic order temperature. We further reveal the interplay of Dirac mass gaps and local magnetic defects. We find that in high defect regions, the Dirac mass gap collapses. Ab initio and coupled Dirac cone model calculations provide insight into the microscopic origin of the correlation between defect density and spatial gap variations. This work provides unambiguous identification of the Dirac mass gap in MnBi2Te4, and by revealing the microscopic origin of its gap variation, establishes a material design principle for realizing exotic states in intrinsic magnetic topological insulators.
