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Formation of moiré interlayer excitons in space and time

Authors :
Schmitt, David
Bange, Jan Philipp
Bennecke, Wiebke
AlMutairi, AbdulAziz
Meneghini, Giuseppe
Watanabe, Kenji
Taniguchi, Takashi
Steil, Daniel
Luke, D. Russell
Weitz, R. Thomas
Steil, Sabine
Jansen, G. S. Matthijs
Brem, Samuel
Malic, Ermin
Hofmann, Stephan
Reutzel, Marcel
Mathias, Stefan
Source :
Nature; August 2022, Vol. 608 Issue: 7923 p499-503, 5p
Publication Year :
2022

Abstract

Moiré superlattices in atomically thin van der Waals heterostructures hold great promise for extended control of electronic and valleytronic lifetimes1–7, the confinement of excitons in artificial moiré lattices8–13and the formation of exotic quantum phases14–18. Such moiré-induced emergent phenomena are particularly strong for interlayer excitons, where the hole and the electron are localized in different layers of the heterostructure19,20. To exploit the full potential of correlated moiré and exciton physics, a thorough understanding of the ultrafast interlayer exciton formation process and the real-space wavefunction confinement is indispensable. Here we show that femtosecond photoemission momentum microscopy provides quantitative access to these key properties of the moiré interlayer excitons. First, we elucidate that interlayer excitons are dominantly formed through femtosecond exciton–phonon scattering and subsequent charge transfer at the interlayer-hybridized Σ valleys. Second, we show that interlayer excitons exhibit a momentum fingerprint that is a direct hallmark of the superlattice moiré modification. Third, we reconstruct the wavefunction distribution of the electronic part of the exciton and compare the size with the real-space moiré superlattice. Our work provides direct access to interlayer exciton formation dynamics in space and time and reveals opportunities to study correlated moiré and exciton physics for the future realization of exotic quantum phases of matter.

Details

Language :
English
ISSN :
00280836 and 14764687
Volume :
608
Issue :
7923
Database :
Supplemental Index
Journal :
Nature
Publication Type :
Periodical
Accession number :
ejs60622952
Full Text :
https://doi.org/10.1038/s41586-022-04977-7