Regensburg 2016 – scientific programme
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O: Fachverband Oberflächenphysik
O 48: Electronic Structure: Surface Magnetism and Spin Phenomena
O 48.3: Poster
Tuesday, March 8, 2016, 18:15–20:30, Poster E
Laser induced DC photocurrents in a Topological Insulator thin film — •Nina Meyer1, Thomas Schumann1, Dagmar Butkovicová2, Eva Schmoranzerová2, Helena Reichlová3, Gregor Mussler4, Petr Nemec2, Detlev Grützmacher4, and Markus Münzenberg1 — 1Institute of Physics, Ernst-Moritz-Arndt University, Greifswald,Germany — 2Faculty of Mathematics and Physics, Charles University, Prague, Czech Republic — 3Institute of Physics ASCR v.v.i., Prague, Czech Republic — 4Peter Grünberg Institute (PGI-9), Jülich, Germany
Recent experiments give evidence that the optical excitation of spin-polarized surface states of topological insulators (TI) can launch electron currents along the surface whose direction can be controlled by varying the polarization of the driving light [1]. We generated a photocurrent by illuminating TI (Bi, Sb)2Te3 thin films with laser light whose polarization changes periodically. The laser light was focused to a 6 µm spot on the device by an objective. We found and will discuss that the photocurrent has at least two parts on different time dynamics. Furthermore we determined different Parameters like [1] and show their dependence on polarization and additional experimental parameters. The films with a thickness of 20 nm were structured to Hall bar devices.
We acknowledge funding through DFG priority program SPP "Topological Insulators" and DAAD PPP Czech Republic "FemtomagTopo". [1] J. W. McIver, D. Hsieh, H. Steinberg, P. Jarillo-Herrero and N. Gedik, Nature Nanotechnology 7, 96-100 (2012)