The electro-momentum couplings (ISF project)

Metamaterials are architected composites designed to exhibit extraordinary properties, either in value or in their fundamental nature. Of particular importance are metamaterials in elastodynamics, engineered to shape elastic waves for various applications such as noise reduction, cloaking and energy harvesting.
The first approach was to design metamaterials with negative parameters. Gradually, the focus has shifted towards Willis materials, which offer a larger design space for wave manipulation relative to other metamaterials. The additional design parameters of Willis materials are nonlocal constitutive properties that couple stress with velocity and linear momentum with strain.
We recognized that it is possible to go beyond Willis materials using piezoelectric constituents: by doing so, we further enlarged the design space with effective properties that couple electric displacement with velocity, and linear momentum with electric field. We showed that the now termed ‘electro-momentum’ couplings can be harnessed for elastic waves manipulation, since they modify the wave velocity and introduce directional phase angle. Importantly, we showed that these effects can be tuned by adjusting the electric circuit conditions.