Phonons in Multi-Welled Carbon Nanotubes

The phonons in multi‐walled carbon nanotubes (MWNTs) are studied within a force‐constant model and a continuum model. Special attention is given the low‐frequency modes that are most affected by nesting of the separate layers into a MWNT. First, a MWNT has four acoustic branches, which determine its elastic properties and low‐temperature specific heat. Secondly, due to the interlayer interactions, the so‐called breathing modes of the separate layers are modified into breathing‐like modes of the MWNTs. The results of the calculation of the Raman intensity agree well with an available experimental Raman spectra of a double‐walled nanotube sample.