Thermal conductivity of single-walled carbon nanotubes

We have measured the thermal conductivity (κ) of bulk samples of single-walled nanotube (SWNT) bundles. The thermal conductivity of SWNTʹs is found to be large, and dominated by phonons at all temperatures. κ(T) of SWNTʹs is linear in temperature from 7 K to 25 K, increases slope between 25 K and 40 K, and rises monotonically with temperature to above room temperature. The data can be fit by a single-scattering-time model; the model confirms that the low-temperature linear behavior is due to the thermal conductivity of a single one-dimensional phonon subband, and that the phonon mean free path is of order 100 nm.