2016/11/30 by Fernando de Juan, Adolfo G. Grushin, Takahiro Morimoto +1 · 5 citations
Physics and Astronomy · #cond-mat.str-el
paper · pdf · doi:10.1038/ncomms15995
published as Nature Communications 8, 15995 (2017) · 4+5 pages, 3 figures, published version
arxiv created 2017/07/25 · arxiv updated 2017/07/27
The circular photogalvanic effect (CPGE) is the part of a photocurrent that switches depending on the sense of circular polarization of the incident light. It has been consistently observed in systems without inversion symmetry and depends on non-universal material details. Here we find that in a class of Weyl semimetals (e.g. SrSi2) and three-dimensional Rashba materials (e.g. doped Te) without inversion and mirror symmetries, the injection contribution to the CPGE trace is effectively quantized in terms of the fundamental constants e, h, c and ε0 with no material-dependent parameters. This is so because the CPGE directly measures the topological charge of Weyl points, and non-quantized corrections from disorder and additional bands can be small over a significant range of incident frequencies. Moreover, the magnitude of the CPGE induced by a Weyl node is relatively large, which enables the direct detection of the monopole charge with current techniques.