Thermal conductivity of carbon nanotube peapods

Thermal conductivity of a $(10,10)$ carbon nanotube filled with C₆₀ fullerenes (or a peapod) is computed using direct molecular-dynamics simulations with the Tersoff-Brenner potential for C-C bonding interactions and the van der Waals potential for nonbonding interactions. The temperature-dependent thermal conductivity of the peapod, while showing qualitatively similar behavior to that of an unfilled carbon nanotube, is found to be higher than the nanotube at all temperatures. This is in agreement with recent experimental observations. The increase in thermal conductivity in the peapod is explained through (a) an energy transfer between fullerenes and nanotube due to low-frequency radial vibration coupling between fullerenes and nanotube, and (b) energy transfer along the peapod axis due to fullerene-fullerene collisions.