Berlin 2018 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 52: Optical properties & Photonic crystals
HL 52.1: Vortrag
Freitag, 16. März 2018, 09:30–09:45, EW 201
Gyrotropic effects in trigonal tellurium studied from first principles — •Stepan S. Tsirkin1,2, Pablo Aguado Puente1,2, and Ivo Souza1,3 — 1Centro de Física de Materiales, Universidad del País Vasco, 20018 San Sebastián, Spain — 2Donostia International Physics Centre, 20018 San Sebastián, Spain — 3Ikerbasque Foundation, 48013 Bilbao, Spain
We present a combined ab initio study of several gyrotropic effects in p-doped trigonal tellurium (effects that reverse direction with the handedness of the spiral chains in the atomic structure). The key ingredients in our study are the Berry curvature and the orbital magnetic moment induced in the Bloch states by the broken spatial inversion symmetry of the crystal structure.
We show that the observed sign reversal of the circular photogalvanic effect with temperature can be explained by the presence of Weyl points near the bottom of the conduction band acting as sources and sinks of Berry curvature. The passage of a current along the trigonal axis induces a parallel magnetization, leading to the occurence of Faraday rotation alongside natural optical rotation. In agreement with experiment, we find that when infrared light propagates antiparallel to the current at low doping, the induced Faraday effect enhances the natural optical rotation. The plane of polarization rotates in the opposite sense to the bonded atoms in the spiral chains, in agreement with a recent experimental determination of the handedness of a Te crystal that contradicts earlier reports.
The work is published as arXiv:1710.03204.