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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 15: 2D Materials 4 (joint session HL/CPP/DS)
CPP 15.5: Vortrag
Dienstag, 6. September 2022, 11:00–11:15, H36
Theoretical description of moiré excitons in twisted MoSe2 homobilayers — •Ruven Hübner1, Malte Kremser2, Viviana Villafañe2, Marko M. Petrić3, Matthias Florian4, Alexander Steinhoff1, Mackillo Kira4, Nathan P. Wilson2, Andreas V. Stier2, Kai Muller3, and Jonathan J. Finley2 — 1Institut für Theoretische Physik, Universität Bremen, Bremen, Germany — 2Walter Schottky Institut and Physik Department, Technische Universität München, Garching, Germany — 3Walter Schottky Institut and Department of Electrical and Computer Engineering, Technische Universität München, Garching, Germany — 4University of Michigan, Dept. of Electrical Engineering and Computer Science, Ann Arbor, MI, USA
By introducing a twist between multiple monolayers of transition metal dichalcogenides we can observe superstructures with a new periodicity - namely the moiré lattice. Its size depends on the twist angle and therefore offers the possibility to modify properties like exciton energies as a function of the twist angle. We demonstrate, how DFT calculations of an untwisted MoSe2 bilayer allow us to locally model the band variation inside the moiré unit cell at all dominant high symmetry points of the Brillouin zone. The resulting model provides access to arbitrary moiré potentials experienced by different exciton species and allows us to calculate their twist angle dependent spectra. For all twist angles we assign the lowest energy to interlayer excitons formed between the Γ- and K-valley. The twist angle dependent shift of 5 meV per degree for small angles is in good agreement with experiment.