Dresden 2017 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 66: Graphene: Electronic Properties, Structure and Substrate Interaction I (joint session DY, DS, HL, MA, O, TT, organized by O)
TT 66.9: Vortrag
Donnerstag, 23. März 2017, 12:30–12:45, WIL A317
Giant magneto-photoelectric effect at a graphene edge — •Friedemann Queisser, Ralf Schützhold, Jens Sonntag, Annika Kurzmann, Martin Geller, and Axel Lorke — Fakultät für Physik, Universität Duisburg-Essen, Lotharstraße, Duisburg 47048, Germany
Graphene is a promising material for optical or infrared absorption, as its pseudo-relativistic energy-momentum relation allows for a broad absorption bandwidth. An efficient charge separation can be achieved at a graphene edge in a magnetic field. By solving the Dirac equation, it can be shown that particles and holes move in antipodal directions along the edge [1]. Motivated by the proposed mechanism, an surprisingly high magneto-photocurrent has been measured in suspended graphene [2]. The observed photo-responsitivity (100 incident photons create up to 17 particle-hole pairs) strongly exceeds the predicted value. A possible mechanism to explain the amplification of the magneto-photoeffect relies on the strong Coulomb interaction in graphene: Due to the huge effective fine-structure constant (αgraphene≫ αQED) and the enlarged phase space at the graphene edge, inelastic (Auger-type) scattering amplifies the magneto-photocurrent.
[1] F. Queisser and R. Schützhold Phys. Rev. Lett. 111, 046601 (2013)
[2] J. Sonntag, A. Kurzmann, M. Geller, F. Queisser, A. Lorke, R. Schützhold, arXiv:1505.01762