Moiré excitons in MoSe2-WSe2 heterobilayers and heterotrilayers

Layered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twiste...

Full description

Saved in:
Bibliographic Details
Published in:Nature communications 2021-03, Vol.12 (1), p.1656-1656, Article 1656
Main Authors: Förg, Michael, Baimuratov, Anvar S., Kruchinin, Stanislav Yu, Vovk, Ilia A., Scherzer, Johannes, Förste, Jonathan, Funk, Victor, Watanabe, Kenji, Taniguchi, Takashi, Högele, Alexander
Format: Article
Language:English
Subjects:
639/766/119/1000/1018
639/925/357/1018
Bilayers
Chalcogenides
Emission
Emissions
Excitons
Heterostructures
Humanities and Social Sciences
Hybridization
Interlayers
Luminescence
Molybdenum compounds
Momentum
multidisciplinary
Multilayers
Phonons
Photoluminescence
Photons
Science
Science (multidisciplinary)
Spatial variations
Transition metal compounds
Transport phenomena
Two dimensional materials
Valleys
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Layered two-dimensional materials exhibit rich transport and optical phenomena in twisted or lattice-incommensurate heterostructures with spatial variations of interlayer hybridization arising from moiré interference effects. Here, we report experimental and theoretical studies of excitons in twisted heterobilayers and heterotrilayers of transition metal dichalcogenides. Using MoSe 2 -WSe 2 stacks as representative realizations of twisted van der Waals bilayer and trilayer heterostructures, we observe contrasting optical signatures and interpret them in the theoretical framework of interlayer moiré excitons in different spin and valley configurations. We conclude that the photoluminescence of MoSe 2 -WSe 2 heterobilayer is consistent with joint contributions from radiatively decaying valley-direct interlayer excitons and phonon-assisted emission from momentum-indirect reservoirs that reside in spatially distinct regions of moiré supercells, whereas the heterotrilayer emission is entirely due to momentum-dark interlayer excitons of hybrid-layer valleys. Our results highlight the profound role of interlayer hybridization for transition metal dichalcogenide heterostacks and other realizations of multi-layered semiconductor van der Waals heterostructures. Here, the authors show that the photoluminescence of MoSe 2 /WSe 2 heterobilayers is dominated by valley-direct excitons, whereas, in heterotrilayers, interlayer hybridization turns momentum-indirect interlayer excitons into energetically lowest states with phonon-assisted emission.
ISSN:2041-1723
2041-1723
DOI:10.1038/s41467-021-21822-z