Dual-Functional Thermal Metamaterials: Decoupling Heat Flux and Temperature Fields for Advanced Thermal Management.

Thermal metamaterials offer a powerful platform for precise thermal management, with exceptional potential in applications such as thermal camouflage, protection, and energy utilization. However, the inherent coupling of heat flux and temperature fields, governed by Fourier's law, limits existing thermal metamaterials to single functionality. For instance, in a classic thermal cloak, both heat flux and temperature gradients are absent within the cloaked region, repelling both fields similarly. Here, a design theory is proposed for dual-functional metamaterials that decouples the functions of heat flux and temperature fields through coordinate transformations along field lines, enabling their independent control. As proof of concept, six dual-functional meta-devices are developed, where the heat flux and temperature fields independently exhibit functions such as cloak, concentrator, and rotation. Furthermore, the Finite Element Method (FEM) is extended, enabling the programmable design of dual-functional thermal metamaterials. The work not only provides a universal design framework for independent functionality in coupled physical fields, but also offers potential applications extending to fields such as electronics, acoustics, and mechanics.