Trajectory of the anomalous Hall effect towards the quantized state in a ferromagnetic topological insulator
Trajectory of the anomalous Hall effect towards the quantized state in a ferromagnetic topological insulator
复制标题
DOI：
10.1038/nphys3053
复制
发表时间：
2014-10-01
期刊：
影响因子：
19.6
通讯作者：
Tokura, Y.
中科院分区：
文献类型：
--
作者：
Checkelsky, J. G.;Yoshimi, R.;Tokura, Y.
拓扑绝缘体是在其表面上具有受保护的无间隙模式的体电子绝缘体（1-5）。通过铁磁性破坏这些系统中的时间反转对称性会诱导出一个以零磁场量子化霍尔响应为特征的带隙态-量子反常霍尔（QAH）态（6-8）。一个关键的问题，仍然是实验上未探索的是这种新型的量子霍尔（QH）状态与以前已知的轨道驱动QH状态的关系。在这里，我们实验表明，表现出QAH状态的铁磁拓扑绝缘体的QH效应的全局相图很好地描述。通过映射QAH相附近的电导率张量，我们发现了量子临界性和离域行为的证据（9，10），这些行为可以通过QH基态的重整化群性质定量描述（11，12）。这个结果表明，这个QAH状态可以在控制QH状态的对应状态定律的背景下理解（13，14）。
Topological insulators are bulk electronic insulators with symmetry-protected gapless modes on their surfaces(1-5). Breaking time-reversal symmetry in these systems via ferromagnetism induces a gapped state characterized by a zero magnetic field quantized Hall response-the quantum anomalous Hall (QAH) state(6-8). A key question that has remained experimentally unexplored is the relationship of this new type of quantum Hall (QH) state with the previously known orbitally driven QH states. Here, we show experimentally that a ferromagnetic topological insulator exhibiting the QAH state is well described by the global phase diagram of the QH effect. By mapping the conductivity tensor in the vicinity of the QAH phase, we find evidence for quantum criticality and delocalization behaviour(9,10) that can quantitatively be described by the renormalization group properties of the QH ground state(11,12). This result demonstrates that this QAH state can be understood within the context of the law of corresponding states that governs the QH state(13,14).