Dresden 2020 – scientific programme
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MA: Fachverband Magnetismus
MA 48: Ultrafast Electron Dynamics III (joint session O/MA)
MA 48.1: Talk
Thursday, March 19, 2020, 10:30–10:45, WIL B321
THz-induced oscillations of the band structures in the topological insulator Bi2Te3 — •Suguru Ito1, Johannes Reimann1, Stefan Schlauderer2, Christoph Schmid2, Fabian Langer2, Sebastian Baierl2, Josef Freudenstein2, Manuel Meierhofer2, Konstantin Kokh3, Oleg Tereshchenko3, Akio Kimura4, Christoph Lange2, Jens Güdde1, Rupert Huber2, and Ulrich Höfer1 — 1Fachbereich Physik, Philipps-Universität Marburg, Germany — 2Fakultät für Physik, Universität Regensburg, Germany — 3Novosibirsk State University, Russia — 4Graduate School of Science, Hiroshima University, Japan
Time- and angle-resolved photoemission spectroscopy (time-resolved ARPES) is a powerful tool to map ultrafast dynamics occurring in electronic band structures. New opportunities arise in combination with THz excitation. As demonstrated recently for the topological surface bands of Bi2Te3, THz-ARPES is capable of mapping the dynamics of electrical currents in k-space with sub-cycle time resolution [1]. Here, we show that the THz light field also induces oscillations of the electronic bands on a time scale longer than the duration of the field transient. Frequency analysis implies the origin in atomic displacements but reveals the existence of oscillation modes that cannot be attributed to phonons in bulk Bi2Te3. Our results suggest another perspective of THz-ARPES, the capability to track band-structure engineering by light. We will discuss the experiment and compare with electronic structure calculations.
[1] J. Reimann et al. Nature 562, 396 (2018).