Bidirectional phonon emission in two-dimensional heterostructures triggered by ultrafast charge transfer

Aditya Sood, Jonah B. Haber, Johan Carlström, Elizabeth A. Peterson, Elyse Barre, Johnathan D. Georgaras, Alexander H.M. Reid, Xiaozhe Shen, Marc E. Zajac, Emma C. Regan, Jie Yang, Takashi Taniguchi, Kenji Watanabe, Feng Wang, Xijie Wang, Jeffrey B. Neaton, Tony F. Heinz, Aaron M. Lindenberg, Felipe H. da Jornada, Archana Raja

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Photoinduced charge transfer in van der Waals heterostructures occurs on the 100 fs timescale despite weak interlayer coupling and momentum mismatch. However, little is understood about the microscopic mechanism behind this ultrafast process and the role of the lattice in mediating it. Here, using femtosecond electron diffraction, we directly visualize lattice dynamics in photoexcited heterostructures of WSe2/WS2 monolayers. Following the selective excitation of WSe2, we measure the concurrent heating of both WSe2 and WS2 on a picosecond timescale—an observation that is not explained by phonon transport across the interface. Using first-principles calculations, we identify a fast channel involving an electronic state hybridized across the heterostructure, enabling phonon-assisted interlayer transfer of photoexcited electrons. Phonons are emitted in both layers on the femtosecond timescale via this channel, consistent with the simultaneous lattice heating observed experimentally. Taken together, our work indicates strong electron–phonon coupling via layer-hybridized electronic states—a novel route to control energy transport across atomic junctions.

Original languageEnglish (US)
Pages (from-to)29-35
Number of pages7
JournalNature Nanotechnology
Volume18
Issue number1
DOIs
StatePublished - Jan 2023
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Bioengineering
  • Atomic and Molecular Physics, and Optics
  • Electrical and Electronic Engineering
  • Biomedical Engineering
  • General Materials Science

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