发表机构
Jamia Millia Islamia（贾米娅米利亚伊斯兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究在二维Rashba节线系统中发现，平行磁场可诱导非线性霍尔效应，并通过调节该场实现拓扑相变，非线性霍尔响应的符号变化特征可作为探测该相变的有效探针。
AI 中文摘要
我们研究了二维Rashba自旋轨道耦合节线电子系统中的线性和非线性霍尔效应。我们考虑了线性霍尔效应的两种情况，即Berry曲率诱导的反常霍尔效应和垂直磁场诱导的整数量子霍尔效应。我们观察到，该系统沿节线边界存在一个拓扑能隙，该能隙强烈依赖于节线的半径和Rashba自旋轨道相互作用的强度，从而产生量子反常霍尔效应。随后，我们加入一个垂直均匀磁场，并获得了精确的朗道能级，这些能级在环边界附近表现出斜率随磁场变化的符号反转。这导致通过调节磁场，在同一能带中量子霍尔电导发生符号反转。最重要的是，我们还表明，当磁场严格平行于系统时，它可以诱导Berry曲率的各向异性，从而导致非线性霍尔效应的出现。此外，调节平行场可以关闭并重新打开拓扑能隙，导致从拓扑Chern绝缘体到平凡绝缘体的反向拓扑相变。非线性霍尔效应在两种相中都持续存在，但其对化学势的依赖性表现出不同的特征。值得注意的是，非线性霍尔响应在Chern绝缘相中表现出符号变化的峰结构，而在平凡绝缘相中则表现出单一符号的响应。这些不同的特征表明，非线性霍尔效应可以作为研究这种拓扑相变的探针。
英文摘要
We investigate the linear and nonlinear Hall effects in a two-dimensional Rashba spin-orbit coupled nodal ring electronic system. We consider both the cases of linear Hall effect, the Berry curvature induced anomalous Hall and the perpendicular magnetic field-induced integer quantum Hall effect. We observe that the system exhibits a topological gap along the boundary of the nodal ring that strongly depends on the radius of the nodal ring and the strength of the Rashba spin-orbit interaction, resulting in the quantum anomalous Hall effect. Subsequently, we include a perpendicular uniform magnetic field and obtain the exact Landau levels that exhibit sign reversal in the slope with magnetic field around the ring boundary. This causes a sign reversal in the quantum Hall conductivity in the same band by tuning the magnetic field. Most importantly, we also show that when the magnetic field is strictly parallel to the system, it can induce an anisotropy to the Berry curvature that leads to the emergence of the nonlinear Hall effect. Additionally, tuning the parallel field can close and reopen the topological gap, resulting in the reverse topological phase transition from the topological Chern insulator to a trivial insulator. The nonlinear Hall effect remains persistent in both phases, but its dependence on the chemical potential exhibits distinct signatures. Noticeably, the nonlinear Hall response exhibits a sign-changing peak structure in Chern insulating phase whereas it displays a single-sign response in trivial insulating phase. These distinct signatures suggest that nonlinear Hall can serve as a probe to study such a topological phase transition.
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