• mardi 14 février 2017

Séminaire Nanoélectronique Quantique : Adolfo Grushin

15h00 // Salle « Remy Lemaire » (K223)

Institut Néel
25 avenue des martyrs - Grenoble

Quantized circular photogalvanic effect in Weyl semimetals

Adolfo Grushin (Department of Physics, UC Berkeley et Institut Néel, CNRS & UGA)

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. 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 CPGE trace is effectively quantized in terms of the combination of fundamental constant e^3/h^2 with no material-dependent parameters. This is so because the CPGE directly measures the topological charge of Weyl points near the Fermi surface, 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.

F. de Juan, A. G. Grushin, T. Morimoto, J. E. Moore, ArXiv : 1611.05887

Contact : aggrushin@berkeley.edu


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juillet 2017 | septembre 2017