Thermal conductivity in nanotubes and nanotube bundles

Nanotubes show a very interesting behaviour of lattice thermal conductivity depending on the tube diameter, with very high thermal conductivities for small diameters. In bundles of nanotubes, the thermal conductivity is affected by the reduced dimensionality of the phonon system. Here, an evaluation of lattice thermal conductivity in nanotubes at low temperatures is proposed in the framework of an armchair lattice model. In spite of its simplicity, the model is able to provide an evaluation of thermal transport in carbon nanotubes and nanotube bundles, with an appreciable agreement with experimental data. A short discussion on thermal transport in nanowires and on the Landauer approach at thermal conduction in nanostructures will be also included.