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HL: Fachverband Halbleiterphysik
HL 33: Poster II
HL 33.18: Poster
Wednesday, March 29, 2023, 17:00–19:00, P1
Coherent coupling dynamics between excitonic complexes in a MoSe 2 monolayer — •Daniel Wigger1, Aleksander Rodek2, Thilo Hahn3, James Howarth4, Takashi Taniguchi5, Kenji Watanabe5, Marek Potemski2,6, Piotr Kossacki2, and Jacek Kasprzak2,7 — 1School of Physics, Trinity College Dublin, Ireland — 2Faculty of Physics, University of Warsaw, Poland — 3Institute of Solid State Theory, University of Münster, Germany — 4National Graphene Institute, University of Manchester, UK — 5National Institute for Materials Science, Tsukuba, Japan — 6Laboratoire National desChamps Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, Grenoble, France — 7Université Grenoble Alpes, CNRS, France
In modern heterostructures of layered van der Waals materials that combine graphene, hBN, and TMDCs it is possible to deterministically control the density of free charge carries in a TMDC monolayer. With this approach and the ultrafast nonlinear four-wave mixing (FWM) spectroscopy technique we study the coherent coupling dynamics between neutral and charged excitons in a MoSe2 monolayer. We demonstrate that the so-called Raman coherence between the two exciton species leads to characteristic quantum beats in the FWM signal. By exploiting 2D-FWM spectra, we can conclude that the bias dependent change of dipole strength between the exciton types is not sufficient to explain the experimental findings. Therefore, we conclude that the tuning of the free carrier density directly affects the coherent coupling between neutral and charged excitons.