MoS2 单层中非线性异常霍尔效应的应变调控

Due to the time reversal symmetry, the linear anomalous Hall effect (AHE) usually vanishes in MoS2 monolayer. In contrast, the nonlinear AHE plays an essential role in such system when the uniaxial strain breaks the C3v symmetry and eventually results in a nonzero Berry curvature dipole (BCD). We find that not only the magnitude of the AHE but also the nonlinear Hall angle can be tuned by the strain. Especially the nonlinear Hall angle exhibits a deep relationship which is analogy to the birefringence phenomenon in optics. It actually results from the pseudotensor nature of the BCD moment. Besides the ordinary positive and negative crystals in optics, there are two more birefringence-like cases corresponding to an imaginary refraction index ratio in monolayer MoS2. Our findings shed lights on the strain controlled electronic devices based on the two-dimensional (2D) materials with BCD.