Chirality-dependent frequency shift of radial breathing mode in metallic carbon nanotubes

Ken Ichi Sasaki, Riichiro Saito, Gene Dresselhaus, Mildred S. Dresselhaus, Hootan Farhat, Jing Kong

Research output: Contribution to journalArticle

51 Citations (Scopus)

Abstract

A phonon frequency shift of the radial breathing mode for metallic single wall carbon nanotubes is predicted as a function of Fermi energy. Armchair nanotubes do not show any frequency shift while zigzag nanotubes exhibit phonon softening, but this softening is not associated with the broadening. This chirality dependence originates from a curvature-induced energy gap and a special electron-phonon coupling mechanism for radial breathing modes. Because of the particle-hole symmetry, only the off-site deformation potential contributes to the frequency shift. On the other hand, the on-site potential contributes to the Raman intensity, and the radial breathing mode intensity is stronger than that of the G band. The relationship between the chirality dependence of the frequency shift of the radial breathing mode and the Γ point optical-phonon frequency shift is discussed.

Original languageEnglish
Article number235405
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume78
Issue number23
DOIs
Publication statusPublished - 2008 Dec 1

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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