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HL: Fachverband Halbleiterphysik
HL 9: 2D Materials and Heterostructures: Interlayer Excitons
HL 9.10: Talk
Monday, March 18, 2024, 17:30–17:45, EW 201
Investigating moiré interlayer excitons under the influence of atomic reconstructions — •Nils-Erik Schütte1, Carl Emil Mørch Nielsen2, Niclas Götting1, Frederik Lohof1, Gabriel Bester2, and Christopher Gies1 — 1Institute for Theoretical Physics, University of Bremen — 2Institute of Physical Chemistry, University of Hamburg
The moiré pattern which emerges due to a relative rotation between two monolayers of transition metal dichalcogenides (TMDs) features a long lattice period for small twist angles. The resulting band structure modulation acts as an effective potential for interlayer excitons (IXs). However, lattice reconstructions change the moiré potential which forms broader and deeper potential minima, realizing a periodic array of quantum wells for IXs. This serves as an implementation of the Bose-Hubbard (BH) model for the simulation of correlated excitonic states.
Expanding on previous results [1], we describe the correlated behavior of IXs in the moiré lattice with an extended BH model taking into account non-local interactions and a material realistic modelling of the dielectric screening. Considering interatomic forces, we discuss how the BH parameters and especially the excitonic wave functions are influenced by local atomic reconstructions. Furthermore, by solving the BH model with a sublattice mean-field description, we address the question in how far correlated states of moiré excitons emerge at different twist angles and integer as well as fractional lattice fillings.
[1] Götting et al., Phys. Rev. B 105, 165419 (2022)
Keywords: Moiré Physics; Interlayer Excitons; Bose-Hubbard Model; Quantum Phases