Abstract
We report the experimental and numerical realization of a pseudospin-dependent acoustic topological insulator based on two sonic crystals constructed by the same regular hexagonal rods. Based on the zone folding mechanism, we obtain double Dirac cones with a four-fold deterministic degeneracy in the sonic crystal, and realize a band inversion and topological phase transition by rotating the rods. We observe the topologically protected one-way sound propagation of pseudospin-dependent edge states in a designed topological insulator composed of two selected sonic crystals with different rotation angles of the rods. Furthermore, we experimentally demonstrate the robustness of topological sound propagation against two types of defects, in which the edge states are almost immune to backscattering, and remain pseudospin-dependent characteristics. Our work provides a diverse route for designing tunable topological functional sound devices.
Highlights
In the past few years, acoustic topological insulators (ATIs) have become a hot topic in the area of acoustics for its great potential applications, such as acoustic-noise reduction [1], acoustic beam splitter [2] and acoustic communications [3]
By rotating these rods, we obtain another type of sonic crystals (SCs) composed of the unit B, in which the rotation angles of a central rod and six surrounding rods are θ0 and θ, respectively
The regular hexagon rods are fabricated with polymethyl methacrylate (PMMA), which is used to meet the condition of sound hard boundary in numerical models
Summary
In the past few years, acoustic topological insulators (ATIs) have become a hot topic in the area of acoustics for its great potential applications, such as acoustic-noise reduction [1], acoustic beam splitter [2] and acoustic communications [3]. By introducing the zone folding mechanism, a type of pseudospin-dependent ATI without depending on a fixed filling ratio was proposed [30, 31], in which the observed double Dirac cones were a deterministic degeneracy. These types of pseudospin-dependent ATIs were designed by fictitious soft metamaterial rods [30] and three circular rods with different radius [31], and the. Based on the zone folding mechanism, we obtain double Dirac cones with the deterministic degeneracy, and realize a band inversion by rotating the rods in the SCs. we design an ATI composed of two SCs with different rotation angles of the rods, and observe a one-way sound propagation of topological edge states. We experimentally demonstrate the robustness of the topologically protected sound propagation against two types of defects of a disorder and a bend
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
