We measure the electron-phonon (e-ph) coupling matrix elements of the G band in semiconducting carbon nanotubes (CNTs) in comparison to the radial breathing mode (RBM). The experimental result for the G+ mode [Γ-point longitudinal optical (LO) phonon] at the E22 transition suggests an e-ph coupling strength of approximately 30 meV or 12.5 eV/Å which is within the expected range of 23 meV to 83 meV for a 1-nm-diameter CNT. This coupling (as the square of the matrix elements) for the G+ mode is an order of magnitude higher than that of the RBM and other measured phonon modes. In addition we assign a Raman feature observed around 1700 cm-1 to be the combination mode of a low energy (∼400 cm-1) and a high energy (∼1300 cm-1) zone-boundary phonon. Both the phonon energies and phonon dispersions of those modes support the assignment.
|Original language||English (US)|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Aug 5 2011|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics