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Updated: Aug 24, 2025

Characterization of Thermal Transport in One-dimensional Solid Materials

Characterization of Thermal Transport in One-dimensional Solid Materials

Published on: January 26, 2014

Thermal Willis Coupling in Spatiotemporal Diffusive Metamaterials.

Liujun Xu^1,2, Guoqiang Xu¹, Jiaxin Li¹

¹Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583, Singapore.

Physical Review Letters

|October 21, 2022

Summary

This summary is machine-generated.

Researchers created spatiotemporal diffusive metamaterials exhibiting thermal Willis coupling. This novel coupling enables asymmetric heat diffusion, controllable by material modulation, opening avenues for directional thermal management.

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Area of Science:

Metamaterials Science
Thermodynamics
Transport Phenomena

Background:

Willis coupling, typically seen in wave systems, arises from bianisotropy or chirality.
Such coupling is absent in standard diffusion systems governed by Fourier's law.

Purpose of the Study:

To introduce and investigate thermal Willis coupling in spatiotemporal diffusive metamaterials.
To explore the manipulation of heat flux and temperature change rate through modulated material properties.

Main Methods:

Modulating thermal conductivity and mass density in heat transfer to create spatiotemporal diffusive metamaterials.
Modifying Fourier's law to account for homogenized spatiotemporal parameters.
Analyzing the emergence of thermal Willis coupling between heat flux and temperature change rate.

Main Results:

Demonstrated thermal Willis coupling in diffusive metamaterials by altering thermal conductivity and mass density.
Observed asymmetric heat diffusion driven by thermal Willis coupling.
Showcased the reversibility of diffusion direction at a critical modulation point.
Confirmed the robustness of thermal Willis coupling even with modulation of thermal conductivity alone.

Conclusions:

Spatiotemporal diffusive metamaterials can exhibit thermal Willis coupling, enabling asymmetric heat diffusion.
The direction of diffusion is controllable and reversible via spatiotemporal modulation.
These findings offer potential for directional diffusion applications and understanding nonequilibrium energy transfer.