TY - JOUR
T1 - Interface-Mediated Resonant Raman Enhancement for Shear Modes in a 2D Polar Metal
AU - He, Wen
AU - Wetherington, Maxwell T.
AU - Ulman, Kanchan Ajit
AU - Robinson, Joshua A.
AU - Quek, Su Ying
N1 - Funding Information:
W.H., K.A.U., and S.Y.Q. acknowledge funding from Grants MOE2016-T2-2-132, MOE2017-T2-2-139, and MOE2018-T3-1-005 from the Ministry of Education (MOE), Singapore, funding from the MOE Research Scholarship Block, and funding from the Singapore National Research Foundation, Prime Minister’s Office, under its medium-sized center program. Computations were performed on the NUS Graphene Research Centre cluster and National Supercomputing Centre Singapore (NSCC). J.A.R. and M.T.W. are supported in part by Horiba and the Penn State Center for Nanoscale Science through the National Science Foundation Grant DMR-2011839. All Raman measurements were performed in the Materials Research Institute at the Materials Characterization Laboratory at Penn State University.
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/9/1
Y1 - 2022/9/1
N2 - 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.
AB - 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.
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U2 - 10.1021/acs.jpcc.2c04433
DO - 10.1021/acs.jpcc.2c04433
M3 - Article
AN - SCOPUS:85136716727
SN - 1932-7447
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
ER -