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O: Fachverband Oberflächenphysik
O 100: Topological Insulators II
O 100.2: Talk
Friday, March 11, 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.