Detail study of the Raman-active modes in carbon nanotubes

Abstract

The Raman-active A1-modes in carbon nanotubes are often used for characterizing nanotube samples. The fully-symmetric radial-breathing mode and the high-energy mode (HEM) have small non-radial and non-tangential components, respectively. Neglecting these components results in errors for phonon frequency and electron-phonon coupling calculations. We present a model to estimate these non-radial components. For the HEM we find an anharmonicity that stems from the three-fold coordination of the C atoms. © 2007 WILEY-VCH Verlag GmbH & Co. KGaA.