Reaching new levels of wave scattering via piezoelectric metamaterials and electro-momentum coupling

Piezoelectric materials are materials that can convert mechanical energy into electrical energy (and vice versa). In addition to the well-known electromechanical interaction between mechanical deformation and electric fields, a recent discovery revealed that the macroscopic linear momentum of piezoelectric materials is also coupled with the electric field. This means that their kinetic movement can be controlled by the electric field. This effect is termed electro-momentum (EM) coupling and provides a new design degree of freedom for piezoelectric devices with better properties and dynamic performance. In this talk, theoretical bounds of EM coupling in wave scattering will be discussed, which can provide valuable information on estimating the performance space of piezoelectric metamaterials for various applications such as acoustic sensing and energy harvesting. The results show that scattering performance from EM coupling can be of the same order of magnitude as that of the scatterer’s geometric features, such as shape and size, which are considered major factors for scattering performance. Furthermore, its capability of promising wave manipulation will be demonstrated, i.e., tunable scattering-cloaking piezoelectric devices via EM coupling. Moreover, how material properties and geometrical microstructures affect EM coupling will be investigated, which allows researchers to precisely control EM coupling in piezoelectric materials.