Minimum Thermal Conductivity of Superlattices

TL;DR

This paper investigates the phonon thermal conductivity in multilayer superlattices, revealing a minimum conductivity at a specific layer thickness due to a transition from particle to wave transport regimes.

Contribution

It provides a theoretical calculation of the minimum thermal conductivity in superlattices, highlighting the crossover from particle to wave phonon transport modes.

Findings

Thermal conductivity exhibits a minimum at a certain layer thickness.

Transition from particle to wave transport occurs near the mean free path.

Minimum conductivity occurs at layers slightly smaller than the phonon mean free path.

Abstract

The phonon thermal conductivity of a multilayer is calculated for transport perpendicular to the layers. There is a cross over between particle transport for thick layers to wave transport for thin layers. The calculations shows that the conductivity has a minimum value for a layer thickness somewhat smaller then the mean free path of the phonons.