Abstract
By using first principles density functional perturbation theory, we computed the phonon dispersions of 4 nm diameter (5,0) carbon nanotubes. We investigated the development of phonon anomalies as the Fermi surface sharpens. The soft modes are related to the nesting features in the electronic band structure. We found that two phonon branches are strongly renormalized by electron-phonon coupling, and the anomaly of one phonon branch is traced to interband coupling while the anomaly of another phonon branch is due to intraband coupling. The complex behavior is explained using a simple model.
- Received 10 December 2007
DOI:https://doi.org/10.1103/PhysRevB.77.235407
©2008 American Physical Society