Design of metamaterials permits separate control of currents

The ability to control thermal and electric currents is essential to many modern-day technologies. However, thermoelectric effects, such as the Seebeck effect, can cause thermal and electric currents to couple and flow in the same direction when thermal and voltage gradients are applied, which makes it difficult to create materials that can independently control thermal and electric currents.

Shi et al. developed a new way to design materials that allow independent control of the thermoelectrically coupled thermal and electric currents. Specifically, they modeled designs of metamaterials, which are composite materials that possess properties not typically found in natural materials.

The authors designed the geometry of the composite layered materials to control the directions of the currents based on concepts from thermodynamics and circuit theory. The constituent materials have components connected in-series and in-parallel to allow and restrict the flow of thermal and electric currents in certain directions.

“This is a method that can be adopted to any type of geometry and applied thermal and voltage gradients,” said author Lilia Woods. The authors suggest that this technique could also be applied to coupled phenomena beyond thermal and electric currents, including electro-osmosis, thermal-osmosis, and thermophoresis.

This design scheme’s ability to independently control thermal and electric currents could be beneficial in the development of components for electronic devices. Next, the authors plan to explore how they can use their method to design metamaterials to improve the energy efficiency of thermoelectric devices.

Source: “Thermoelectric transport control with metamaterial composites,” by Wencong Shi, Troy Stedman, and Lilia M. Woods, Journal of Applied Physics (2020). The article can be accessed at https://doi.org/10.1063/5.0004037 .