Thermal conductivity of an ultrathin carbon nanotube with an X-shaped junction

The thermal conductivity of the ultrathin carbon nanotube with and without an X-shaped junction was investigated using nonequilibrium molecular-dynamics simulations. The ultrathin carbon nanotube exhibits superhigh thermal conductivity. The thermal conductivity of the nanotube with junctions was 20-80% less than that of a straight nanotube depending on temperature. There is a jump in the temperature profile around the junction, contributing to a larger temperature gradient and reduction in the thermal conductivity. The thermal conductivity of armchair nanotube junctions is sensitive to the topological structures at the junction region.