Interface-Mediated Resonant Raman Enhancement for Shear Modes in a 2D Polar Metal

Wen He, Maxwell T. Wetherington, Kanchan Ajit Ulman, Joshua A. Robinson, Su Ying Quek

Research output: Contribution to journalArticlepeer-review

1 Scopus citations

Abstract

2D polar metals synthesized by confinement heteroepitaxy at the SiC/graphene interface are covalently bound to the SiC substrate. In this work, we elucidate the importance of the SiC substrate, and specifically the Ga/Si interface, on the low-frequency resonant Raman spectra of 2D Ga on SiC. The low-frequency Raman modes are dominated by in-plane shear modes in 2D Ga. We show that the frequency of these shear modes is modified by the presence of the substrate for few-layer Ga and that these shear modes couple strongly to the electronic states corresponding to the interface Ga and Si atoms. Consequently, resonant Raman enhancement occurs at laser incident energies that are resonant with the interband optical transitions involving these interface Ga and Si states. This resonant Raman enhancement is observed in laser-energy-dependent measurements, an experimental signature of the strong electron-phonon coupling present in these 2D polar metals.

Original languageEnglish (US)
Pages (from-to)14581-14589
Number of pages9
JournalJournal of Physical Chemistry C
Volume126
Issue number34
DOIs
StatePublished - Sep 1 2022

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • General Energy
  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films

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