Tunable Acoustic Valley–Hall Edge States in Reconfigurable Phononic Elastic Waveguides

Controlling the flow of mechanical energy in elastic structures has been a long-standing challenge in many areas of engineering, particularly those dealing with vibrations and structure-borne noise. In light of recent studies on the quantum valley Hall effect in electronic systems, the authors show that a00exc00exo00exu00exs00ext00exi00exc topological edge states can be achieved, at a boundary or interface between two elastic waveguides having broken space-inversion symmetry. The topological properties of such waveguides can be tuned by applying a controlled strain field, while the resulting edge states show a relatively high insensitivity to defects.