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arXiv 2006.05615cond-mat.mes-hall
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扭曲WSe $_2$的巨非线性霍尔效应

Giant nonlinear Hall effect in twisted WSe$_2$

Meizhen Huang, Zefei Wu, Jinxin Hu, Xiangbin Cai, En Li, Liheng An, Xuemeng Feng, Ziqing Ye, Nian Lin, Kam Tuen Law, Ning Wang

摘要:

最近发现的非线性霍尔效应(NHE)在一些非相互作用系统提供了一种新的机制,产生二次谐波电霍尔信号下的时间反转对称条件。在这里,我们介绍了一种新的方法来工程NHE通过使用扭曲莫尔结构。我们发现,扭曲的WSe $_2$双层膜呈现NHE时,调整费米能级的莫尔平坦带。在第一莫尔带的半填充附近,非线性霍尔信号显示出尖锐的峰值,产生效率比先前实验中的产生效率高至少两个数量级。我们认为,巨大的NHE和发散发电效率源于质量发散型连续莫特跃迁,这一点通过电阻率测量得到了证明。这项工作不仅展示了相互作用效应如何耦合到Berry曲率偶极子产生新的量子现象,而且还展示了NHE测量可以为开发研究量子临界性的新工具提供什么。

英文摘要:

The recently discovered nonlinear Hall effect (NHE) in a few non-interacting systems provides a novel mechanism to generate second harmonic electrical Hall signals under time-reversal-symmetric conditions. Here, we introduce a new approach to engineering NHE by using twisted moiré structures. We find that the twisted WSe$_2$ bilayer exhibits a NHE when tuning the Fermi level to the moiré flat bands. Near half-filling of the first moiré band, the nonlinear Hall signal shows a sharp peak with the generation efficiency at least two orders of magnitude larger than those in previous experiments. We propose that the giant NHE and diverging generation efficiency originate from a mass-diverging type continuous Mott transition, which is evidenced by resistivity measurements. This work demonstrates not only how interaction effects can couple to Berry curvature dipoles to produce novel quantum phenomena, but also what NHE measurements can provide for developing a new tool to study the quantum criticality.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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