Band Signatures for Strong Nonlinear Hall Effect in Bilayer WTe2
Band Signatures for Strong Nonlinear Hall Effect in Bilayer WTe2
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双层 WTe2 中强非线性霍尔效应的能带特征
DOI：
10.1103/physrevlett.121.266601
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发表时间：
2018-12-26
影响因子：
8.6
通讯作者：
Xie, X. C.
中科院分区：
文献类型：
--
作者：
Du, Z. Z.;Wang, C. M.;Xie, X. C.
打破离散或晶体对称性的非常规反应为探索新兴的物理系统和材料开辟了道路。通过破坏反转对称性，即使在存在时间反转对称性的情况下，也可以观察到与传统霍尔效应完全不同的非线性霍尔信号。低对称性二维材料是非线性霍尔效应的有希望的候选者，但是当可以测量强非线性霍尔信号时，特别是它与能带结构性质的联系，则知之甚少。通过模型分析，我们发现在倾斜带反交叉和带反转附近存在显著的非线性霍尔信号。这些能带特征可以用来解释最近在二维WTe 2实验中出现的强非线性霍尔效应。这封信不仅对分析非线性霍尔效应的输运特征，而且对探索突发材料中的非常规响应具有指导意义。
Unconventional responses upon breaking discrete or crystal symmetries open avenues for exploring emergent physical systems and materials. By breaking inversion symmetry, a nonlinear Hall signal can be observed, even in the presence of time-reversal symmetry, quite different from the conventional Hall effects. Low-symmetry two-dimensional materials are promising candidates for the nonlinear Hall effect, but it is less known when a strong nonlinear Hall signal can be measured, in particular, its connections with the band-structure properties. By using model analysis, we find prominent nonlinear Hall signals near tilted band anticrossings and band inversions. These band signatures can be used to explain the strong nonlinear Hall effect in the recent experiments on two-dimensional WTe2. This Letter will be instructive not only for analyzing the transport signatures of the nonlinear Hall effect but also for exploring unconventional responses in emergent materials.