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

doi:10.1038/s41565-022-01253-7

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

Nat Nanotechnol. 2023 Jan;18(1):29-35. doi: 10.1038/s41565-022-01253-7. Epub 2022 Dec 21.

Authors

Aditya Sood^#^{1

2}, Jonah B Haber^#³, Johan Carlström⁴, Elizabeth A Peterson^{3

4}, Elyse Barre^{5

6}, Johnathan D Georgaras⁷, Alexander H M Reid⁸, Xiaozhe Shen⁸, Marc E Zajac⁷, Emma C Regan^{3

4

9}, Jie Yang⁸, Takashi Taniguchi¹⁰, Kenji Watanabe¹¹, Feng Wang³, Xijie Wang⁸, Jeffrey B Neaton^{3

4

12}, Tony F Heinz^{5

6}, Aaron M Lindenberg^{13

14}, Felipe H da Jornada¹⁵, Archana Raja¹⁶

Affiliations

¹ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. [email protected].
² Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. [email protected].
³ Department of Physics, University of California Berkeley, Berkeley, CA, USA.
⁴ Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
⁵ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁶ Department of Applied Physics, Stanford University, Stanford, CA, USA.
⁷ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA.
⁸ SLAC National Accelerator Laboratory, Menlo Park, CA, USA.
⁹ Graduate Group in Applied Science and Technology, University of California Berkeley, Berkeley, CA, USA.
¹⁰ International Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Japan.
¹¹ Research Center for Functional Materials, National Institute for Materials Science, Tsukuba, Japan.
¹² Kavli Energy NanoScience Institute, University of California Berkeley, Berkeley, CA, USA.
¹³ Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, Menlo Park, CA, USA. [email protected].
¹⁴ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. [email protected].
¹⁵ Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA. [email protected].
¹⁶ Lawrence Berkeley National Laboratory, Berkeley, CA, USA. [email protected].

^# Contributed equally.

PMID: 36543882
DOI: 10.1038/s41565-022-01253-7

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.

Abstract

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