Regensburg 2022 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 20: 2D Materials 4 (joint session HL/CPP/DS)
HL 20.8: Vortrag
Mittwoch, 7. September 2022, 11:30–11:45, H36
Capacitively and inductively coupled excitons in bilayer MoS2 — •Lukas Sponfeldner1, Nadine Leisgang1, Shivangi Shree2, Ioannis Paradisanos2, Kenji Watanabe3, Takashi Taniguchi4, Cedric Robert2, Delphine Lagarde2, Andrea Balocchi2, Xavier Marie2, Iann C. Gerber2, Bernhard Urbaszek2, and Richard J. Warburton1 — 1Department of Physics, University of Basel — 2Université de Toulouse, INSA-CNRS-UPS, LPCNO — 3Research Center for Functional Materials, National Institute for Materials Science — 4International Center for Materials Nanoarchitectonics, National Institute for Materials Science
Exciton-exciton couplings in semiconductors lead to a plethora of phenomena such as nonlinear optical effects and quantum condensation. Transition-metal dichalcogenides constitute a versatile platform to study these effects as the excitons are very robust and their couplings can be controlled by exploiting their spin and valley properties.
Here, we probe exciton-exciton couplings in gated-homobilayer MoS2. Using a driven-coupled oscillator model it is shown that the measured optical susceptibility reveals both the magnitude and the phase of the coupling constants. The interlayer excitons (IE) and intralayer B-excitons couple via a 0-phase (capacitive) coupling; the IE and the intralayer A-excitons couple via a π-phase (inductive) coupling. Using the IE as a sensor, the A-B intravalley exchange coupling is determined, a result which is also relevant for a monolayer. Finally, we realize a bright and highly tunable lowest-energy momentum-direct exciton at high electric fields.