We report on a numerical study of quantum diffusion over $\mu \mathrm{m}$ lengths in defect-free multiwalled nanotubes. The intershell coupling allows the wave packet spreading over several shells, and when their periodicities along the nanotube axis are incommensurate, electronic propagation is shown to follow a nonballistic law if a sufficient number of shells are involved in conduction. This results in magnetotransport properties which are exceptional for a disorder free system.

• Received 17 April 2001

DOI:https://doi.org/10.1103/PhysRevB.64.121401