Vibrations and Heat Transfer in Glasses: the role played by Disorder

TL;DR

This paper reviews how structural disorder in amorphous materials affects their vibrational properties and heat transfer, explaining the unusual temperature dependence of thermal conductivity through disorder-dependent vibrational modes.

Contribution

It provides a comprehensive review linking disorder in glasses to their vibrational eigenmodes and thermal conductivity behavior, offering a unified interpretation.

Findings

Disorder increases heat capacity compared to crystals.

Disorder decreases thermal conductivity in amorphous materials.

Temperature dependence of thermal conductivity can be explained by vibrational eigenmodes.

Abstract

Amorphous materials are also distinguished from crystals by their thermal properties. The structural disorder seems to be responsible both for a significant increase in heat capacity compared to crystals of the same composition, but also for a significant decrease in thermal conductivity. The temperature dependence of thermal conductivity, unusual for common interpretations of solid-state physics, gave rise to a lot of debates. We review in this article different interpretations of thermal conductivity in amorphous materials. We show finally that the temperature dependence of thermal conductivity in dielectric materials can be understood by relating it to the disorder-dependent harmonic vibrational eigenmodes.