Tunable acoustic valley edge states in a flow-free resonator system

Abstract

Recent developments in valleytronic materials have inspired developing various analogs of acoustic crystal systems for manipulating airborne acoustic transmissions. Earlier designs of acoustic topological insulators were normally characterized by untunable bulky geometries and a narrow effective frequency response, which limited the design and development of practical acoustic devices. Here, we design a gapless topologically protected acoustic resonator system based on valley edge states in reconfigurable phononic crystals. By simply rotating the modified spiral springs to adjust the inner radius without altering the lattice structure, this method can be utilized to realize backscattering immune, tunable, broadband, and miniaturized functional acoustic applications. This study offers a design route in valley phenomena for acoustic topological flow-free resonator systems.