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DS: Fachverband Dünne Schichten

DS 22: 2D semiconductors and van der Waals heterostructures V (joint session HL/DS/O)

DS 22.5: Vortrag

Mittwoch, 18. März 2020, 10:30–10:45, POT 81

Edge photogalvanic effect driven by optical alignment in bi-layer graphene — •Susanne Candussio¹, Mikhail V. Durnev², Jun Yin³, Artem Mishchenko³, Helene Plank¹, Vasily V. Bel'kov², Sergey A. Tarasenko², Vladimir Fal'ko³, and Sergey D. Ganichev¹ — ¹University of Regensburg, 93040 Regensburg, Germany — ²Ioffe Institute, 194021 St. Petersburg, Russia — ³University of Manchester, Manchester M13 9PL, UK

We report on the observation of the edge electric current excited in bi-layer graphene by terahertz laser radiation. We show that the current generation belongs to the class of second order in electric field phenomena and is controlled by the orientation of the THz electric field polarization plane. Application of a magnetic field normal to the graphene plane leads to a phase shift in the polarization dependence. In strong magnetic field the current exhibit 1/B-magnetooscillations with a period consistent with that of the Shubnikov-de-Haas effect and amplitude by an order of magnitude large as compared to the current at zero field measured under the same conditions. The developed microscopic theory shows that the current is formed in the edges vicinity limited by the mean-free path and originates from optical alignment of free carriers and scattering at the edges, which naturally break the P-symmetry. The observed magnetooscillations of the photocurrent are attributed to the formation of the Landau levels.