Dresden 2014 – scientific programme

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TT: Fachverband Tiefe Temperaturen

TT 13: Topological Insulators: Mostly Structure and Electronic Structure (organized by HL)

TT 13.5: Talk

Monday, March 31, 2014, 10:30–10:45, POT 051

Room temperature high frequency transport of Dirac fermions in MBE grown Sb₂Te₃ based topological insulators — •T. Herrmann¹, P. Olbrich¹, S.N. Danilov¹, Ch. Weyrich³, J. Kampmeier³, G. Mussler³, D. Grützmacher³, L. Plucinski³, C.M. Schneider³, M. Eschbach³, L.E. Golub², V.V. Bel’kov², and S.D. Ganichev¹ — ¹University of Regensburg, Regensburg, Germany — ²Ioffe Institute, St. Petersburg, Russia — ³Peter Grünberg Institute (PGI) & Jülich Aachen Research Alliance (JARA-FIT), Research Center Jülich, Jülich, Germany

We report on the observation of terahertz (THz) laser radiation induced currents in epitaxially grown Sb₂Te₃ based topological insulators (TI) [1]. We demonstrate that the excitation of the sample with linearly polarized THz radiation results in a photoresponse solely stemming from the surface states of the 3D TI. Our analysis shows that the photocurrent is caused by the photogalvanic effect [2], which emerges in the surface states but is forbidden in the centrosymmetric bulk material. As an important result our measurements demonstrate that the high frequency transport can be obtained in the Dirac fermion system even at room temperature.

[1] Plucinski et al.; J. Appl. Phys. 113, 053706 (2013)

[2] Weber et al.; Phys. Rev. B 77, 245304 (2008)