Theoretical and experimental demonstrations of the transversely symmetric and antisymmetric properties of topological edge states

Abstract

Topological phononics are well known for their topological edge states due to the backscattering immunity and pseudospin dependent phonon transportation. Here, we study two types of topological edge states on valley phononic crystal plate. We magnify the transversely symmetric and antisymmetric property by observing the displacement distribution in both simulation and experiment. We underline the theoretical origin of transversely symmetric and antisymmetric property based on a simplified mass-spring model, i.e., the combination of the phase difference caused by the periodicity of PC plate and the phase difference between sites p and q in unit cell. Our results enrich the features of topological edge states, and offer the possibility for designing mechanical device or controlling the wave propagation along phonon circuits.