How Does van der Waals Confinement Enhance Phonon Transport?

TL;DR

This paper demonstrates that van der Waals confinement can significantly enhance phonon transport, challenging the traditional view of vdW interactions as a hindrance and providing new insights for heat management.

Contribution

It reveals that vdW confinement can boost phonon transport and provides a physical mechanism explaining this enhancement through molecular dynamics simulations.

Findings

vdW confinement more than doubles thermal conductivity in nanostructures

Confined vdW potential barriers reduce atomic thermal displacements

Reduced phonon scattering facilitates improved heat transport

Abstract

The van der Waals (vdW) interactions exist in reality universally and play an important role in physics. Here, we show the study on the mechanism of vdW interactions on phonon transport in atomic scale, which would boost developments in heat management and energy conversion. Commonly, the vdW interactions are regarded as a hindrance in phonon transport. Here, we propose that the vdW confinement will enhance phonon transport. Through molecular dynamics simulations, it shows that the vdW confinement makes more than two-fold enhancement on thermal conductivity of both polyethylene single chain and graphene nanoribbon. The quantitative analyses of morphology, local vdW potential energy and dynamical properties are carried out to reveal the underlying physical mechanism. It is found that the confined vdW potential barriers reduce the atomic thermal displacement magnitudes, thus lead to less phonon scattering and facilitate thermal transport. Our study offers a new strategy to modulate the heat transport.