Hydrodynamic Phonon Transport: Past, Present, and Prospect

TL;DR

This paper reviews the history, recent advances, and future prospects of hydrodynamic phonon transport, emphasizing its significance in high thermal conductivity materials and the underlying physical mechanisms.

Contribution

It provides a comprehensive overview of past and recent studies on hydrodynamic phonon transport, highlighting new insights and future research directions.

Findings

Hydrodynamic phonon transport can significantly enhance thermal conductivity in materials.

Normal scattering processes play a crucial role in enabling hydrodynamic behavior.

Propagation of second sound demonstrates collective phonon motion in certain materials.

Abstract

The hydrodynamic phonon transport was studied several decades ago for verifying the quantum theory of lattice thermal transport. Recent prediction of significant hydrodynamic phonon transport in graphitic materials shows its practical importance for high thermal conductivity materials and brought a renewed attention. As the study on this topic has been inactive to some extent for several decades, we aim at providing a brief overview of the past studies as well as very recent studies. The topics we discuss in this chapter include the collective motion of phonons, several approaches to solve the Peierls-Boltzmann transport equation for hydrodynamic phonon transport, the role of normal scattering for thermal resistance, and the propagation of second sound. Then, we close this chapter with our perspectives for the future studies and the practical implication of hydrodynamic phonon transport.