Regensburg 2016 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 84: Topological Insulators II
(Joint session of DS, HL, MA, O and TT organized by O)

TT 84.2: Vortrag

Freitag, 11. März 2016, 09:45–10:00, H15

Teraherz-Induced Chiral Edge Photogalvanic currents in 2D HgTe Topological Insulators — •Kathrin-Maria Dantscher¹, Dimitry A. Kozlov², Maria-Theresia Scherr¹, Sebastian Gebert¹, Vasily V. Bel’kov³, Nikolay N. Mikhailov², Sergey A. Dvoretskii², Ze Dong Kvon², and Sergey D. Ganichev¹ — ¹University of Regensburg, Regensburg, Germany — ²Institute of Semiconductor Physics, Novosibirsk, Russia — ³Ioffe Institute, St. Petersburg, Russia

We report on the observation of a chiral photogalvanic current generated in the topological protected edge states of 2D topological insulators fabricated on the basis of 8 nm thick HgTe quantum wells. Illuminating the sample with circularly polarized terahertz radiation and picking-up the signal along the edges we detected a photocurrent whose direction reverses by switching radiation polarization from right- to left-handed one. The influence of the magnetic field, the temperature and the angle of incidence of the radiation to these photocurrents are investigated. We demonstrate that circularly polarized radiation, which, according to selection rules, excites only electrons with a certain spin, results in an imbalance of electron distribution in the k-space and causes a spin polarized electric current.