The energy dispersion of the D* (G') band shows a strong diameter dependence according to Raman measurements on double walled carbon nanotubes. The Raman shift of the small diameter inner tubes shows an average softening. There is an oscillation around an average linear behavior with slopes of 108 cm-1/eV and 61 cm-1/eV for the outer and inner tubes, respectively. We show that the experimental observation can be reproduced by simple model calculations if the curvature effects are taken into account. The phonon softening with increasing curvature was proven by first principles calculations.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics