Remarkable reduction of thermal conductivity in graphyne nanotubes by local resonance

Abstract

By using equilibrium molecular dynamics simulations and lattice dynamic calculations, we investigate the thermal transport properties of graphyne nanotubes (GNTs). The results demonstrate that the GNTs exhibit relatively low thermal conductivity, which is approximately 10–25% of that in a carbon nanotube. Detailed lattice dynamic analyses indicate that the presence of sp carbon atoms can induce local resonance modes in the low frequency region, which results in the remarkable decrease of thermal conductivity. Meanwhile, the high-frequency phonon lifetimes also drop because of the vibrational mismatch between sp and sp2 carbon atoms (enhanced phonon scattering). Our results show the local resonance of phonons is an important mechanism for the reduction of thermal conductivity in low-dimensional nanostructures.