Strong Surface-Enhanced Coherent Phonon Generation in van der Waals Materials

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review

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Author(s)

  • Christian Brennan
  • Alan G. Joly
  • Chih-Feng Wang
  • Ti Xie
  • Brian T. O’Callahan
  • Kevin Crampton
  • Alem Teklu
  • Leilei Shi
  • Ming Hu
  • Qian Zhang
  • Narayanan Kuthirummal
  • Hasitha Suriya Arachchige
  • Apoorva Chaturvedi
  • David Mandrus
  • Cheng Gong
  • Yu Gong

Detail(s)

Original languageEnglish
Pages (from-to)10442-10450
Journal / PublicationJournal of Physical Chemistry Letters
Volume15
Issue number42
Online published10 Oct 2024
Publication statusPublished - 24 Oct 2024

Abstract

Terahertz (THz) coherent phonons have emerged as promising candidates for the next generation of high-speed, low-energy information carriers in atomically thin phononic or phonon-integrated on-chip devices. However, effectively manipulating THz coherent phonons remains a significant challenge. In this study, we investigated THz coherent phonon generation in exfoliated van der Waals (vdW) flakes of Fe3GeTe2, Fe5GeTe2, and FePS3. We successfully generated the THz A1g coherent phonon mode in these vdW flakes. An innovative approach involved partially exfoliating vdW flakes on a gold substrate and partially on a silicon (Si) substrate to compare the THz coherent phonon generation between both sides. Interestingly, we observed a significantly enhanced THz coherent phonon in the vdW/gold area compared with that in the vdW/Si area. Frequency-domain Raman mapping across the vdW flakes corroborated these findings. Numerical simulations further indicated a stronger enhanced surface field in vdW/gold structures than in vdW/Si structures. Consequently, we attribute the observed enhancement in THz coherent phonon generation to the increased surface field on the gold substrate. This enhancement was consistent across the three different vdW materials studied, suggesting the universality of this strategy. Our results hold promise for advancing the design of THz phononic and phonon-integrated devices. © 2024 American Chemical Society.

Citation Format(s)

Strong Surface-Enhanced Coherent Phonon Generation in van der Waals Materials. / Brennan, Christian; Joly, Alan G.; Wang, Chih-Feng et al.
In: Journal of Physical Chemistry Letters, Vol. 15, No. 42, 24.10.2024, p. 10442-10450.

Research output: Journal Publications and ReviewsRGC 21 - Publication in refereed journalpeer-review