| Phonons are the main carriers of heat in materials and they play a major role in the thermal behavior of the material in the nanoscale regime. In this study, we have investigated how vibrational energy of phonons is changed during the heat flow through carbon nanotubes. The variation of phonon energy of an armchair (7,7), zigzag (10,0), and chiral (6,3) single-walled carbon nanotubes (SWCNTs) for radial breathing (symmetric stretching) and torsional modes is investigated keeping their length fixed. We varied the annealing temperature from 100K to 800K gradually and studied the conformational change of the CNTs by molecular dynamics simulation. We have also estimated the thermal conductivity of the CNTs by Fourier law using nonequilibrium heat transfer approach. For the radial breathing mode, the energy peaks are observed in a wide range of frequency spectrum but for the torsional mode the peaks are shifted by small amount. In our calculation, maximum thermal conductivity is observed for the armchair CNT. Estimation of thermal conductivity of the SWCNTs at different twisting angles is performed to have an idea of the role of chirality on the thermal conductivity. |
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