Using gate-modulated Raman scattering and electron-phonon interactions to probe single-layer graphene: A different approach to assign phonon combination modes
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Kong_Using gate.pdf
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Author(s)
Sato, K.
Saito, R.
Araujo, P. T.
Mafra, Daniela Lopes
Kong, Jing
Dresselhaus, Mildred
Date Issued
November 2012
Journal
Physical Review B
Publisher
American Physical Society
Citation
Mafra, D. L., J. Kong, K. Sato, R. Saito, M. S. Dresselhaus, and P. T. Araujo. “Using Gate-Modulated Raman Scattering and Electron-Phonon Interactions to Probe Single-Layer Graphene: A Different Approach to Assign Phonon Combination Modes.” Physical Review B 86, no. 19 (November 30, 2012). © 2012 American Physical Society
Version
Final published version
Abstract
Gate-modulated and laser-dependent Raman spectroscopy have been widely used to study q = 0 zone center phonon modes, their self-energy, and their coupling to electrons in graphene systems. In this work we use gate-modulated Raman of q ≠ 0 phonons as a technique to understand the nature of five second-order Raman combination modes observed in the frequency range of 1700–2300 cm[superscript −1] of single-layer graphene (SLG). Anomalous phonon self-energy renormalization phenomena are observed in all five combination modes within this intermediate frequency region, which can clearly be distinguished from one another. By combining the anomalous phonon renormalization effect with the double resonance Raman theory, which includes both phonon dispersion relations and angular dependence of the electron-phonon scattering matrix elements, and by comparing it to the experimentally obtained phonon dispersion, measured by using different laser excitation energies, we can assign each Raman peak to the proper phonon combination mode. This approach should also shed light on the understanding of more complex structures such as few-layer graphene (FLG) and its stacking orders as well as other two-dimensional (2D)-like materials.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Research Laboratory of Electronics
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.86.195434
