Nonlinear optical response of Type-II Weyl fermions in two dimensions

Weyl费米子和Maxwell光子的Berry相位和反常速度

Berry phase and anomalous velocity of Weyl fermions and Maxwell photons

我们考虑两个系统的波动方程的波包解决方案的轨迹，改变了“反常速度”效应的贝里曲率。第一个是描述带电无质量费米子回旋运动的矩阵Weyl方程。第二个是圆柱波导中回音壁模式的麦克斯韦方程组。在无质量费米子的情况下，反常速度被磁矩的贡献所掩盖。在回音壁模式中，反常的速度导致圆周光线以每轨道一个波长的速率沿着圆柱体向上爬行，并且可以被识别为连续版本的Imbert-Federov效应。

Transverse circular photogalvanic effect associated with Lorentz-violating Weyl fermions

Nonlinear optical responses of quantum materials have recently undergone dramatic developments to unveil nontrivial geometry and topology. A remarkable example is the quantized longitudinal circular photogalvanic effect (CPGE) associated with the Chern number of Weyl fermions, while the physics of transverse CPGE in Weyl semimetals remains exclusive. Here, we show that the transverse CPGE of Lorentz invariant Weyl fermions is forced to be zero. We find that the transverse photocurrents of Weyl fermions are associated not only with the Chern numbers but also with the degree of Lorentz-symmetry …

Weyl半金属中的Weyl费米子有多无质量？

How massless are Weyl fermions in Weyl semimetals?

本文发现Weyl半金属中相反螺旋度光场在同一节点产生的电流不抵消，源于非线性色散，并提出三叶草场方案控制手性节点的不对称性。