Topological thermal transport

TL;DR

This paper reviews recent advances in topological thermotics, exploring how topological physics can manipulate thermal conduction, convection, and radiation in artificial metamaterials, and discusses future research directions.

Contribution

It introduces the emerging field of topological thermotics, summarizing recent progress in thermal topological phases, exceptional points, and radiation effects, and proposes future research avenues.

Findings

Recent progress in 1D and higher-dimensional thermal topological phases.

Implementation of thermal exceptional points with unique properties.

Demonstrations of topological effects in thermal radiation.

Abstract

Thermal transport is a fundamental mechanism of energy transfer process quite distinct from wave propagation phenomena. It can be manipulated well beyond the possibilities offered by natural materials with a new generation of artificial metamaterials: thermal metamaterials. Topological physics, a focal point in contemporary condensed matter physics, is closely intertwined with thermal metamaterials in recent years. Inspired by topological photonics and topological acoustics in wave metamaterials, a new research field emerged recently, which we dub `topological thermotics', which encompasses three primary branches: topological thermal conduction, convection, and radiation. For topological thermal conduction, we discuss recent advances in both 1D and higher-dimensional thermal topological phases. For topological thermal convection, we discuss the implementation of thermal exceptional points with their unique properties and non-Hermitian thermal topological states. Finally, we review the most recent demonstration of topological effects in the near-field and far-field radiation. Anticipating future developments, we conclude by discussing potential directions of topological thermotics, including the expansion into other diffusion processes such as particle dynamics and plasma physics, and the integration with machine learning techniques.