December 2007, to be published in Physical Review B1


Lattice vibrations in single-wall carbon nanotubes
D. Gunlycke, H. M. Lawler, and C. T. White

We present a study of lattice vibrations in single-wall carbon nanotubes. The study is based on a force-constant model, where the force constants are obtained from a general invariant potential which includes up to fourth-nearest-neighbor interactions. Applying the model, we obtain phonon dispersions and density of states for various types of nanotubes. General low-frequency modes such as ring modes and longitudinal modes are also identified and investigated. They are almost independent of the chiral angle but depend significantly on the radius. The radius dependence is used for scaling, leading to a universal density of states at low frequencies.

© 2008 The American Physical Society.