Ultrafast Control over Stiffening and Softening of Coherent Interlayer Coupling in WSe<sub>2</sub>/WS<sub>2</sub> Heterobilayers

Twisted van der Waals heterostructures have led to emerging layer-dependent correlated physics in moiré potentials. While optoelectronic controls over interlayer electronic coupling have been reported, the concomitant interlayer vibration has not yet been controlled. Here, we report experimental evidence of ultrafast optical control over the amplitude and oscillation period of interlayer breathing phonons in WSe<sub>2</sub>/WS<sub>2</sub> heterobilayers. Femtosecond optical excitation above the Mott density in gate-tuned devices shows as large as 10% changes of stiffening and softening amplitude of coherent phonons. A theoretical model, incorporating both Buckingham and Hartree energies, is presented to elucidate the impact of charge-separated carriers generated by photoexcitation on phonon dynamics. This work, therefore, provides insights for extending optoelectronic engineering into the coherent phonons in moiré systems.

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Publication Details

Journal
Nano Letters
Published
2024-12-12
DOI
https://doi.org/10.1021/acs.nanolett.4c05079
Citations
4
Primary Topic
2D Materials and Applications
Type
article
Field-Weighted Citation Impact
0.47

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article

Ultrafast Control over Stiffening and Softening of Coherent Interlayer Coupling in WSe2/WS2 Heterobilayers

Zhipei Sun, Faisal Ahmed, J.S. Kim, Takashi Taniguchi et al.
4 citations
Nano Letters
2D Materials and Applications
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article

Ultrafast Control over Stiffening and Softening of Coherent Interlayer Coupling in WSe2/WS2 Heterobilayers

Zhipei Sun, Faisal Ahmed, J.S. Kim, Takashi Taniguchi, Kenji Watanabe, Moon‐Ho Jo, Hyunyong Choi, Jeonghyeon Suh, Hongki Min, Sukho Lee
article en
4 citations

Abstract

Twisted van der Waals heterostructures have led to emerging layer-dependent correlated physics in moiré potentials. While optoelectronic controls over interlayer electronic coupling have been reported, the concomitant interlayer vibration has not yet been controlled. Here, we report experimental evidence of ultrafast optical control over the amplitude and oscillation period of interlayer breathing phonons in WSe<sub>2</sub>/WS<sub>2</sub> heterobilayers. Femtosecond optical excitation above the Mott density in gate-tuned devices shows as large as 10% changes of stiffening and softening amplitude of coherent phonons. A theoretical model, incorporating both Buckingham and Hartree energies, is presented to elucidate the impact of charge-separated carriers generated by photoexcitation on phonon dynamics. This work, therefore, provides insights for extending optoelectronic engineering into the coherent phonons in moiré systems.

Nano LettersVol. 24(51)
Pohang University of Science and Technology (KR), Seoul National University (KR), National Institute for Materials Science (JP), Center for Theoretical Physics (PL), Institute for Basic Science (KR), Quantum Technologies (Sweden) (SE), Aalto University (FI)
Seoul National University, National Research Foundation of Korea, Institute for Basic Science
Openalex Percentile: Top 37%
2D Materials and Applications
0.47
DOIOpen Access PDFOpenAlex
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