Zone folding induced topological insulators in phononic crystals

摘要

This letter investigates a flow-free, pseudospin-based acoustic topologicalinsulator. Zone folding, a strategy originated from photonic crystal, is usedto form double Dirac cones in phononic crystal. The lattice symmetry of thephononic crystal is broken by tuning the size of the center "atom" of the unitcell in order to open the nontrivial topological gap. Robust sound one-waypropagation is demonstrated both numerically and experimentally. This studyprovides a flexible approach for realizing acoustic topological insulators,which are promising for applications such as noise control and waveguidedesign.