Manipulating thermal conductivity through substrate coupling

TL;DR

This paper introduces a novel substrate coupling method to manipulate thermal conductivity, showing that substrate interactions can both decrease and increase thermal transport by affecting phonon scattering and band structure.

Contribution

The study reveals that substrate coupling can be used to enhance thermal conductivity by reducing anharmonic phonon scattering, a new approach for thermal management in nanomaterials.

Findings

Substrate coupling can increase thermal conductivity at specific regions.

Thermal conductivity manipulation achieved without altering material structures.

Demonstrated with double-walled carbon nanotubes and ice nanotubes.

Abstract

We report a new approach to the thermal conductivity manipulation -- substrate coupling. Generally, the phonon scattering with substrates can decrease the thermal conductivity, as observed in recent experiments. However, we find that at certain regions, the coupling to substrates can increase the thermal conductivity due to a reduction of anharmonic phonon scattering induced by shift of the phonon band to the low wave vector. In this way, the thermal conductivity can be efficiently manipulated via coupling to different substrates, without changing or destroying the material structures. This idea is demonstrated by calculating the thermal conductivity of modified double-walled carbon nanotubes and also by the ice nanotubes coupled within carbon nanotubes.