Regensburg 2016 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 24: Electronic Structure: Surface Magnetism and Spin Phenomena

MA 24.3: Poster

Dienstag, 8. März 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)