When Chiral Photons Meet Chiral Fermions: Photoinduced Anomalous Hall Effects in Weyl Semimetals
When Chiral Photons Meet Chiral Fermions: Photoinduced Anomalous Hall Effects in Weyl Semimetals
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DOI：
10.1103/physrevlett.116.026805
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发表时间：
2016-01-15
影响因子：
8.6
通讯作者：
Ran, Ying
中科院分区：
文献类型：
--
作者：
Chan, Ching-Kit;Lee, Patrick A.;Ran, Ying
外尔半金属的特征在于三维线性带接触点，称为外尔节点。这些节点成对出现，具有相反的手性。我们表明，这些手征电子的圆偏振光的耦合产生的霍尔电导率没有任何施加的磁场中的平面正交于光的传播。这一现象的出现是因为当所有三个泡利矩阵都被耗尽以形成三维线性色散时，外尔节点不能被间隙化。相反，手征光子的净影响是移动外尔节点的位置。有趣的是，动量位移与节点的手征性紧密相关，从而产生净异常霍尔信号。应用我们的建议，最近发现的TaAs家族的Weyl半金属导致的光致霍尔电导率的数量级估计是在实验范围内。
The Weyl semimetal is characterized by three-dimensional linear band touching points called Weyl nodes. These nodes come in pairs with opposite chiralities. We show that the coupling of circularly polarized photons with these chiral electrons generates a Hall conductivity without any applied magnetic field in the plane orthogonal to the light propagation. This phenomenon comes about because with all three Pauli matrices exhausted to form the three-dimensional linear dispersion, the Weyl nodes cannot be gapped. Rather, the net influence of chiral photons is to shift the positions of the Weyl nodes. Interestingly, the momentum shift is tightly correlated with the chirality of the node to produce a net anomalous Hall signal. Application of our proposal to the recently discovered TaAs family of Weyl semimetals leads to an order-of-magnitude estimate of the photoinduced Hall conductivity which is within the experimentally accessible range.