Acoustic topological one-way waveguides with tunable widths using spinning components

Abstract

We propose the topological one-way waveguide for acoustic waves whose width can be flexibly adjusted. The waveguide is constructed by a heterostructure where an ordinary phononic crystal is sandwiched by two time-reversal-symmetry-broken (TRS-broken) phononic crystals with their cylinders spinning in an opposite manner. The waveguide mode is confined to the ordinary phononic crystal and exhibits the gap-less and asymmetric dispersion. Therefore, we can tune the width of the waveguide by adjusting the thickness of the ordinary phononic crystal, and the waveguide mode is one-way transport which is robust against various types of local disorders and arbitrary bends. Owing to these, this acoustic topological one-way waveguide can meet the requirements of more applications compared with conventional waveguides and conventional one-way waveguides based on chiral surface waves.