谷贝里曲率偶极子诱导的非线性谷霍尔效应
Valley Berry curvature dipole induced nonlinear valley Hall effect
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中文总结 AI 辅助
本文揭示了一种由谷贝里曲率偶极子机制诱导的新型非线性谷霍尔效应，该效应在时间反演不变谷系统中被支持，并可通过调节驱动场方向进行控制，且在应变Nb3SBr7材料中通过第一性原理计算得到验证。
中文摘要 AI 辅助
谷霍尔效应是谷电子学领域的一个标志性效应，近年来的研究已将该效应拓展至非线性领域。在此，我们揭示了一种先前未被探索的非线性谷霍尔效应类型，它源于谷贝里曲率偶极子（vBCD）机制。我们证明，这种非线性谷霍尔效应对于常规的时间反演连接谷是被禁止的，但在具有时间反演不变谷的谷电子系统中得到支持。我们获得了候选层群及vBCD的详细对称性约束。研究表明，非线性谷霍尔响应以及非线性电荷霍尔响应可以通过调节驱动场方向来很好地控制。我们通过有效模型研究和第一性原理计算，在具体材料实例——应变Nb$_{3}$SBr$_{7}$中展示了我们的提议。此外，还讨论了这种vBCD诱导的非线性谷霍尔效应的非局域输运特征。
英文摘要
Valley Hall effect is a signature effect in the field of valleytronics, and recent studies have pushed this effect into the nonlinear regime. Here, we reveal a previously unexplored type of nonlinear valley Hall effect which arises from a valley Berry curvature dipole (vBCD) mechanism. We show this nonlinear valley Hall effect is forbidden for conventional time-reversal-connected valleys, but is supported in the class of valleytronic systems featuring time-reversal-invariant valleys. The candidate layer groups and detailed symmetry constraints on vBCD are obtained. It shows the nonlinear valley Hall response, as well as the nonlinear charge Hall response, can be well controlled by tuning the driving field direction. We demonstrate our proposal in an effective model study and in a concrete material example, strained Nb$_{3}$SBr$_{7}$, by first-principles calculations. The nonlocal transport signature of this vBCD induced nonlinear valley Hall effect is also discussed.
发表机构
- University of Macau（澳门大学）
- Beijing University of Chemical Technology（北京化工大学）
- The Hong Kong Polytechnic University（香港理工大学）
- Fudan University（复旦大学）
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