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MO: Fachverband Molekülphysik
MO 8: Strong-Field and Ultrafast Phenomena (joint session Q/MO)
MO 8.3: Vortrag
Dienstag, 11. März 2025, 11:45–12:00, HS V
Photocurrent control in a light-dressed Floquet topological insulator — •Weizhe Li1, Daniel Lesko1, Tobias Weitz1, Simon Wittigschlager1, Christian Heide1,2, Ofer Neufeld3, and Peter Hommelhoff1,4 — 1Department Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany — 2Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, USA — 3Schulich Faculty of Chemistry, Technion - Israel Institute of Technology, Haifa, Israel — 4Department Physik, Ludwig-Maximilians-Universität München (LMU), 80799 München
Light-dressed materials, based on Floquet engineering, offers unique opportunities to design transient band structures. Most commonly, circularly-polarized dressing light can generate topologically non-trivial nonequilibrium states known as Floquet topological insulators (FTIs) which host a variety of topological phenomena. Floquet engineering with strong optical fields opens routes to optically tunable band structures and devices for petahertz electronics.
Here we demonstrate coherent control of photocurrents in light-dressed graphene. Circularly-polarized laser pulses dress the graphene into an FTI, and phase-locked second harmonic pulses drive electrons in the FTI. We map the resulting dynamics onto two-color phase dependent photocurrents. This approach allows us to measure all-optical anomalous Hall currents and photocurrent circular dichroism. Furthermore, we map out the attosecond Floquet phase by varying the two-color phase. The coherent control of photocurrents in graphene-based FTI connects optics tools to condensed matter physics.
Keywords: Floquet engineering; Topological insulator; Graphene