अमूर्त

Thermal Transport in Multi-Walled Carbon Nanotubes

Hirakjyoti Das

Studies on heat conduction in nano-dimensional structures have raised numerous interests not only because of geometry dependent thermal transport but also apparently controllable heat dissipation in confined regions including the role of defects and impurity atoms. On reducing the structural size from bulk-to-nanoscale dimension, there will be significant alteration of specific heat capacity. So, thermal conductivity goes different in different temperature regimes approaching to a maximal value at 300 K for carbon nanotubes (CNTs). It may be noted that, unlike electronic contribution to the specific heat capacity, the lattice contribution in a 1D system varies as ~T (as compared to ~T3 trend for a 3D system). Though theoretically and practically thermal conductivity measurements have been carried out for SWCNT but no such theoretical works have been performed for double and triple wall carbon nanotube. We first established the theoretical calculation of thermal conductivity of DWCNT and TWCNT which matches with the experimental observations. The novelty of our work lies with the fact that we first found that as the no of walls increase in CNT from single to double to triple, thermal conductivity values decreases due to van der Waals interaction between the atoms of different walls. We see that thermal conductivity of single-wall CNT is very high (~3500 WmK-1), but it gets reduced to ~700 WmK-1 for a double-wall CNT. This drop is ascribed to incoherent heat dissipation owing significantly to the van der Waals interaction among the atoms of different co-axial walls