Multi-band selective acoustic valley transport through band separation of topological interface states

Abstract

Utilizing the coupling strength of local resonance and Bragg scattering, this paper proposes an acoustic valley Hall system to obtain the multi-band selective acoustic valley transport. Under the protection of high crystal symmetry, two deterministic Dirac points appeared at the corner of the first Brillouin zone, and the frequencies of these Dirac points were related to the coupling strength of resonance and Bragg scattering. The rotating-scatterer mechanism was used to realize the valley Hall phase transition. Subsequently, this paper found that the frequency of the edge states had an interface-dependent property through the dispersion relation of the supercell, composed of sonic crystals with different valley Hall phases. Furthermore, the rotation angles of the scatterer could separate the frequency bands of the edge states belonging to different interfaces. Inspired by these interesting discoveries, this paper realized the multi-band selective acoustic valley transport through band separation of topological interface states by numerical calculation and experiment. This study paves a way towards the potential engineering application, such as multi-band communications and filters.