Formation of moiré interlayer excitons in space and time
Artikel i vetenskaplig tidskrift, 2022
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 lattices8-13 and 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.
Författare
David Schmitt
Georg-August-Universität Göttingen
Jan Philipp Bange
Georg-August-Universität Göttingen
Wiebke Bennecke
Georg-August-Universität Göttingen
Abdul Aziz AlMutairi
Department of Engineering
Giuseppe Meneghini
Philipps-Universität Marburg
Kenji Watanabe
National Institute for Materials Science (NIMS)
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Daniel Steil
Georg-August-Universität Göttingen
D. Russell Luke
Georg-August-Universität Göttingen
R. Thomas Weitz
Georg-August-Universität Göttingen
Sabine Steil
Georg-August-Universität Göttingen
G. S.Matthijs Jansen
Georg-August-Universität Göttingen
Samuel Brem
Philipps-Universität Marburg
Ermin Malic
Philipps-Universität Marburg
2D-Tech
Chalmers, Fysik, Kondenserad materie- och materialteori
Stephan Hofmann
Department of Engineering
Marcel Reutzel
Georg-August-Universität Göttingen
Stefan Mathias
Georg-August-Universität Göttingen
Nature
0028-0836 (ISSN) 1476-4687 (eISSN)
Vol. 608 7923 499-503Ämneskategorier
Atom- och molekylfysik och optik
Annan fysik
Den kondenserade materiens fysik
DOI
10.1038/s41586-022-04977-7
PubMed
35978130