Fermi energy dependence of first- and second-order Raman spectra in graphene: Kohn anomaly and quantum interference effect
Name
PhysRevB.94.075104.pdf
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1.59 MB
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Adobe PDF
Checksum (MD5)
71741371756b922c22a08e16916773f9
Author(s)
Hasdeo, Eddwi H.
Nugraha, Ahmad R. T.
Dresselhaus, Mildred
Saito, Riichiro
Date Issued
August 2016
Journal
Physical Review B
Publisher
American Physical Society
Citation
Hasdeo, Eddwi H., Ahmad R. T. Nugraha, Mildred S. Dresselhaus, and Riichiro Saito. "Fermi energy dependence of first- and second-order Raman spectra in graphene: Kohn anomaly and quantum interference effect." Phys. Rev. B 94, 075104 (2016). ©2016 American Physical Society.
Version
Final published version
Abstract
Intensities of the first- and the second-order Raman spectra are calculated as a function of the Fermi energy. We show that the Kohn anomaly effect, i.e., phonon frequency renormalization, in the first-order Raman spectra originates from the phonon renormalization by the interband electron-hole excitation, whereas in the second-order Raman spectra, a competition between the interband and intraband electron-hole excitations takes place. By this calculation, we confirm the presence of different dispersive behaviors of the Raman peak frequency as a function of the Fermi energy for the first- and the second-order Raman spectra, as observed in some previous experiments. Moreover, the calculated results of the Raman intensity sensitively depend on the Fermi energy for both the first- and the second-order Raman spectra, indicating the presence of the quantum interference effect. The electron-phonon matrix element plays an important role in the intensity increase (decrease) of the combination (overtone) phonon modes as a function of the Fermi energy.
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
https://doi.org/10.1103/PhysRevB.94.075104
