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

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A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

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en

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9

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Nano Letters, Volume 24, issue 51, pp. 16391-16399

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 WSe2/WS2 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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Publisher Copyright: © 2024 American Chemical Society.

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Kim, J, Suh, J, Lee, S H, Watanabe, K, Taniguchi, T, Ahmed, F, Sun, Z, Jo, M H, Min, H & Choi, H 2024, 'Ultrafast Control over Stiffening and Softening of Coherent Interlayer Coupling in WSe 2 /WS 2 Heterobilayers', Nano Letters, vol. 24, no. 51, pp. 16391-16399. https://doi.org/10.1021/acs.nanolett.4c05079