Theoretical study of heat conduction in carbon nanotube hetero-junctions

Thermal conductivity of single-wall carbon nanotubes with linear, “Y” and “X” hetero-junctions is studied using nonequilibrium molecular dynamics method. The three types of junctions with almost equal number of point defects show a similar decrease in thermal conductivity compared to that of the pristine carbon nanotube. Thermal conductivity of the nanotubes with different number of point defects is also calculated for a qualitative comparison. The thermal conductivity decreases with the defect number increasing. When the defects form an interface, they can cause a larger decrease in the thermal conductivity of CNT than when they are distributed dispersedly. The number of defects contained in the nanojunction determines the thermal conductivity to a great extent more than the geometrical forms of the nanojunctions. Phonon spectra of these junctions are also analyzed to explore the mechanism of degradation in thermal conductivity of these junctions.