Ultrahigh convergent thermal conductivity of carbon nanotubes from comprehensive atomistic modeling

TL;DR

This study uses atomistic modeling to demonstrate that the thermal conductivity of carbon nanotubes is finite at infinite length, reaching extremely high values due to quantum effects and anharmonic scattering, with implications for heat transport understanding.

Contribution

It provides a comprehensive atomistic modeling approach showing finite thermal conductivity in carbon nanotubes, resolving debates about divergence in 1D systems.

Findings

Thermal conductivity reaches a finite limit at macroscopic lengths.

Quantum effects significantly influence high thermal conductivity.

Anharmonic scattering suppresses divergence in 1D models.

Abstract

Anomalous heat transport in one-dimensional nanostructures, such as nanotubes and nanowires, is a widely debated problem in condensed matter and statistical physics, with contradicting pieces of evidence from experiments and simulations. Using a comprehensive modeling approach, comprised of lattice dynamics and molecular dynamics simulations, we proved that the infinite length limit of the thermal conductivity of a (10,0) single-wall carbon nanotube is finite but this limit is reached only for macroscopic lengths due to thermal phonon mean free path of several millimeters. Our calculations showed that the extremely high thermal conductivity of this system at room temperature is dictated by quantum effects. Modal analysis showed that the divergent nature of thermal conductivity, observed in one-dimensional model systems, is suppressed in carbon nanotubes by anharmonic scattering channels provided by the flexural and optical modes with polarization in the plane orthogonal to the transport direction.