Mixing of the fully symmetric vibrational modes in carbon nanotubes

Abstract

We study the mixing of the fully symmetric modes in single-walled carbon nanotubes with ab initio calculations. With a variational model, we confirm the results from finite-difference calculations. We further analyze the effect of the mixing on the calculation of phonon frequencies and electron-phonon coupling matrix elements Me-ph. We find that neglecting the mixing leads to errors of up to 60% for Me-ph for the radial breathing mode and up to 50 cm-1 difference for the high-energy mode frequency. © 2007 The American Physical Society.