Kohn anomalies in graphene nanoribbons
Name
Sasaki-2009-Kohn anomalies in graphene nanoribbons.pdf
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Author(s) • • • • • • • •
Dresselhaus, Mildred
Wakabayashi, Katsunori
Enoki, Toshiaki
Mori, Takanori
Takai, Kazuyuki
Saito, Riichiro
Murakami, Shuichi
Yamamoto, Masayuki
Sasaki, Ken-ichi
Date Issued
October 2009
Journal
Physical Review B
Publisher
American Physical Society
Citation
Sasaki, Ken-ichi et al. “Kohn anomalies in graphene nanoribbons.” Physical Review B 80.15 (2009): 155450. © 2009 The American Physical Society
Version
Final published version
Abstract
The quantum corrections to the energies of the Γ point optical phonon modes (Kohn anomalies) in graphene nanoribbons (NRs) are investigated. We show theoretically that the longitudinal optical (LO) modes undergo a Kohn anomaly effect, while the transverse optical (TO) modes do not. In relation to Raman spectroscopy, we show that the longitudinal optical modes are not Raman active near the zigzag edge, while the transverse optical modes are not Raman active near the armchair edge. These results are useful for identifying the orientation of the edge of graphene nanoribbons by G band Raman spectroscopy, as is demonstrated experimentally. The differences in the Kohn anomalies for nanoribbons and for metallic single-wall nanotubes are pointed out, and our results are explained in terms of pseudospin effects.
MIT Department
Massachusetts Institute of Technology. Department of Physics
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DOI of Published Version
http://dx.doi.org/10.1103/PhysRevB.80.155450