磁性欧拉带中的弱局域化
Weak localization in magnetic Euler bands
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中文总结 AI 辅助
该研究分析二维磁性欧拉带的电导率量子修正，发现其因涌现有效时间反演对称性表现出正交类弱局域化，揭示有效晶体对称性可改变无序系统的普适类。
中文摘要 AI 辅助
我们研究具有非零欧拉类的二维脆弱拓扑带中因无序导致的电导率量子修正。与拥有两个涡度相反的狄拉克节点的石墨烯不同，具有单位欧拉数的两个能带拥有两个涡度相同的狄拉克点，这可能会影响安德森局域化。值得注意的是，我们基于对称性分析和图解计算，报告了自旋磁性欧拉带中的异常局域化行为。尽管存在自旋轨道耦合和明确破坏物理时间反演对称性的面内磁化，该系统仍表现出正交对称类特有的弱局域化行为。我们证明，这一反直觉现象源于由晶体和时空反演对称性组成的涌现有效时间反演对称性，使其能够取代标准局域化行为。我们的发现表明，有效晶体对称性可从根本上改变无序系统的普适类，使局域化行为独立于狄拉克节点的具体涡度构型。
英文摘要
We study the quantum correction to the conductivity due to disorder in two-dimensional fragile topological bands with nonzero Euler class. Contrary to graphene where two Dirac nodes have opposite vorticities, two bands with a unit Euler number possess two Dirac points with the same vorticity, which may affect the Anderson localization. Most notably, we report an anomalous localization behavior in spinful magnetic Euler bands based on symmetry analysis and diagrammatic calculations. Despite the presence of spin-orbit coupling and an in-plane magnetization that explicitly breaks physical time-reversal symmetry, the system exhibits weak localization behavior characteristic of the orthogonal symmetry class. We demonstrate that this counter-intuitive phenomenon originates from an emergent effective time-reversal symmetry composed of crystalline and spacetime inversion symmetries, allowing it to supersede the standard localization behavior. Our findings reveal that the effective crystalline symmetries can fundamentally alter the universality class of disordered systems, rendering the localization behavior independent of the specific vorticity configuration of Dirac nodes.
