Twist-angle-dependent interlayer exciton diffusion in WS2–WSe2 heterobilayers

The nanoscale periodic potentials introduced by moiré patterns in semiconducting van der Waals heterostructures have emerged as a platform for designing exciton superlattices. However, our understanding of the motion of excitons in moiré potentials is still limited. Here we investigated interlayer e...

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Vydané v:Nature materials Ročník 19; číslo 6; s. 617 - 623
Hlavní autori: Yuan, Long, Zheng, Biyuan, Kunstmann, Jens, Brumme, Thomas, Kuc, Agnieszka Beata, Ma, Chao, Deng, Shibin, Blach, Daria, Pan, Anlian, Huang, Libai
Médium: Journal Article
Jazyk:English
Vydavateľské údaje: London Nature Publishing Group UK 01.06.2020
Nature Publishing Group
Springer Nature - Nature Publishing Group
Predmet:
140/125
639/301/357
639/766/119
Biomaterials
Chemistry
Chemistry and Materials Science
Condensed Matter Physics
Electronic devices
Energy
Excitons
First principles
Heterostructures
Interlayers
Laboratories
Materials Science
Microscopy
Nanotechnology
Optical and Electronic Materials
Physics
Population
Superlattices
Thin films
Transport
Two dimensional materials
ISSN:1476-1122, 1476-4660, 1476-4660
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Shrnutí:The nanoscale periodic potentials introduced by moiré patterns in semiconducting van der Waals heterostructures have emerged as a platform for designing exciton superlattices. However, our understanding of the motion of excitons in moiré potentials is still limited. Here we investigated interlayer exciton dynamics and transport in WS 2 –WSe 2 heterobilayers in time, space and momentum domains using transient absorption microscopy combined with first-principles calculations. We found that the exciton motion is modulated by twist-angle-dependent moiré potentials around 100 meV and deviates from normal diffusion due to the interplay between the moiré potentials and strong exciton–exciton interactions. Our experimental results verified the theoretical prediction of energetically favourable K–Q interlayer excitons and showed exciton-population dynamics that are controlled by the twist-angle-dependent energy difference between the K–Q and K–K excitons. These results form a basis to investigate exciton and spin transport in van der Waals heterostructures, with implications for the design of quantum communication devices. Interlayer exciton dynamics in a van der Waals heterostructure is found to be modulated by the twist angle between the atomically thin layers, elucidating the effect of moiré potentials on exciton motion and providing guidelines to design quantum photonics devices based on 2D materials.
Bibliografia:ObjectType-Article-1
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SC0016356
USDOE Office of Science (SC)
ISSN:1476-1122
1476-4660
1476-4660
DOI:10.1038/s41563-020-0670-3