Observation of elastic Weyl points in ferroelectric based sonic metamaterials

Abstract

The study of Weyl points in electronic systems has recently inspired extensive research in classical systems, such as photonic and acoustic lattices. We construct a single-phase three-dimensional structure, an analog of the honeycomb lattice, and then predict the existence of Weyl points with opposite topological charges (±1) as well as the associated gapless topologically protected surface states. We apply full-scale numerical simulations on the elastic three-dimensional structure and present a clear visualization of the topological surface states that are directional and robust. Such designed lattices can pave the way for novel vibration control and energy harvesting on structures that are ubiquitous in many engineering applications.