Heat conduction in coaxial nanocables of Au nanowire core and carbon nanotube shell: A molecular dynamics simulation

• Au NWs filled in CNTs exhibit helical cylindrical multi-shelled structures.
• Encapsulations of Au NWs increase the thermal conductivity of CNTs.
• Heat transfer enhancement is primarily attributed to VDOS increment in 12-30 THz.
• ETC of filled Au NWs is much lower than PTC of either bare CNTs or nanocables.
• Heat transfer in nanocables is sensitive to tube chiralities and Au filling ratios.

Non-equilibrium molecular dynamics simulations have been employed to calculate the thermal conductivity of coaxial nanocables of Au nanowire core and carbon nanotube shell, i.e. nanotubes filled with nanowires. Our efforts are focused on how the thermal conductivity can be altered in nanocables. By performing analysis on the phonon vibrational density of states, we have revealed that the thermal conductivity of nanocables is 20-42% higher than the corresponding bare nanotubes, due to the interactions of C–C and C–Au and the mass transfer induced by nanowire axial motion. The dependences of thermal conductivity on the temperature, length, diameter, chirality and filling ratio have been investigated. It turns out that the tendencies of nanocable thermal conductivity changing with temperature, length and diameter are similar to bare nanotubes. In addition, the thermal conductivity of nanocables always goes up with the increasing filling ratio. For different chirality types, the zigzag (18, 0) nanocable has the largest thermal conductivity increments, followed by armchair (10, 10) and chiral (14, 7) nanocables.