Berlin 2024 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 53: 2D Materials and Heterostructures: (Twisted) Bilayers (joint session HL/TT)
HL 53.4: Vortrag
Freitag, 22. März 2024, 10:15–10:30, EW 201
Exciton-polaritons in twisted-bilayer heterostructures — •Francesco Troisi1, Hannes Huebener1, Angel Rubio1,3, and Simone Latini2 — 1MPSD, Hamburg, Germany — 2Department of Physics, DTU, Lyngby, Denmark — 3Center for Computational Quantum Physics, Flatiron Institute, Simons Foundation, NYC, USA
2D materials, such as TMDs, have attracted significant attention due to their unique electronic properties, such as tunable bandgap, high emission efficiency, and a strong excitonic binding allowing the formation of stable excitons at room temperature. Excitons in multilayer TMD structures are the object of great interest, as we find both inter- and intra-layer excitons, which give rise to a response at different energies. Previous works show that it is possible to tune the Moiré potential to control their localization, which influences the optical properties.
In the quest to understand and control excitons in novel environments, this study focuses on excitonic behavior for a twisted bilayer MoSe2/WSe2 heterostructure in an optical cavity. Our goal is to produce an all-optical Moiré-like exciton confinement by tuning the cavity. Optical cavities provide a promising approach to controlling material properties by coupling the electronic transitions in the material to the confined photons inside the cavity, which implies photonic and excitonic states cannot be separated. The so-called exciton-polariton states are obtained. In the strong coupling regime, one needs to go beyond the perturbative approach to treat the light-matter problem.
This study utilizes the full diagonalization of the QED problem built from the Wannier equation in k-space and the Moiré potential.
Keywords: QED; Twisted-bilayer heterostructure; Optical cavities; Polaritons; Moire excitons