  Anomalous heat transport in one-dimensional nanostructures, such as nanotubes
and nanowires, is a widely debated problem in condensed matter and statistical
physics, with contradicting pieces of evidence from experiments and
simulations. Using a comprehensive modeling approach, comprised of lattice
dynamics and molecular dynamics simulations, we proved that the infinite length
limit of the thermal conductivity of a (10,0) single-wall carbon nanotube is
finite but this limit is reached only for macroscopic lengths due to thermal
phonon mean free path of several millimeters. Our calculations showed that the
extremely high thermal conductivity of this system at room temperature is
dictated by quantum effects. Modal analysis showed that the divergent nature of
thermal conductivity, observed in one-dimensional model systems, is suppressed
in carbon nanotubes by anharmonic scattering channels provided by the flexural
and optical modes with polarization in the plane orthogonal to the transport
direction.

Mesoscale and Nanoscale Physics;Statistical Mechanics