Multiwalled carbon nanotubes are ballistic conductors at room temperature

Following the experiments of Frank et al. [1], which demonstrated quantum transport in multiwalled carbon nanotubes, there have been several experiments that appear to contradict the main conclusion of that paper, which is that the transport of a MWNT at room temperature is ballistic. Here we demonstrate that the intrinsic resistance of clean-are-produced carbon nanotubes is at most 200 Omega/mum, which implies that the momentum mean free path is greater than 30 mum, which in turn is much larger than the tube length. This implies that these tubes are ballistic. according to the standard definition of ballistic transport. We also show that the contact resistance with mercury is quite large: a nanotube in contact with Hg over 100 nm of its length still represents a 3000 Omega resistance.