Large longitudinal circular photogalvanic effect in a chiral Weyl semimetal

Breaking all of the mirror symmetries in a chiral Weyl semimetal lifts the energy
degeneracy of two Weyl points with opposite Chern numbers. One of the conse-
quences is the large or even quantized circular photogalvanic effect (CPGE)
, which originates from one of the Weyl points by keeping the other node
Pauli-blocked. Here, we report a large photocurrent generated by circularly
polarized light in a chiral Weyl semimetal. Symmetry analysis shows that
the photocurrent is consistent with the longitude CPGE in bulk. The second-order
conductivity spectrum of CPGE in near-infrared and mid-infrared regions is then obtained and
the condition of quantization is examined.