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arXiv · 1611.05887

Quantized circular photogalvanic effect in Weyl semimetals

Fernando de Juan·Adolfo G. Grushin·Takahiro Morimoto·Joel E. Moore
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Abstract

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. SrSi$_2$) 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 $ε_0$ 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.

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Fernando de Juan, Adolfo G. Grushin, Takahiro Morimoto, Joel E. Moore. 2017-07-25. Quantized circular photogalvanic effect in Weyl semimetals. https://doi.org/10.1038/ncomms15995

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