Localized heat diffusion in topological thermal materials

TL;DR

This paper establishes a topological framework for heat diffusion in thermal materials, demonstrating edge states with localized heat dissipation and confirming the bulk-boundary correspondence through experiments.

Contribution

It introduces a continuum model linking Zak phase to thermal edge states, overcoming previous challenges in topological heat transfer analysis.

Findings

Experimental demonstration of topologically protected heat edge states

Analytical proof of thermal bulk-boundary correspondence

Introduction of a state vector linking Zak phase to edge states

Abstract

Various unusual behaviors of artificial materials are governed by their topological properties, among which the edge state at the boundary of a photonic or phononic lattice has been captivated as a popular notion. However, this remarkable bulk-boundary correspondence and the related phenomena are missing in thermal materials. One reason is that heat diffusion is described in a non-Hermitian framework because of its dissipative nature. The other is that the relevant temperature field is mostly composed of modes that extend over wide ranges, making it difficult to be rendered within the tight-binding theory as commonly employed in wave physics. Here, we overcome the above challenges and perform systematic studies on heat diffusion in thermal lattices. Based on a continuum model, we introduce a state vector to link the Zak phase with the existence of the edge state, and thereby analytically prove the thermal bulk-boundary correspondence. We experimentally demonstrate the predicted edge states with a topologically protected and localized heat dissipation capacity. Our finding sets up a solid foundation to explore the topology in novel heat transfer manipulations.