Thermally tunable topological transmission of elastic waves in solid phononic crystals

Abstract

Elastic wave topology materials have attracted widespread attention due to their protection by topological properties, which can accurately guide and control the propagation path of elastic waves. However, the band gaps and topological states in most current metamaterials lack tunability, which limits their practical applications. To enhance the functionality and convenience of elastic wave modulation in engineering applications and achieve the adjustment of the band structures, a solid phononic crystal structure with thermally tunable topological transmission is designed in this paper. Firstly, the effect of temperature on the bulk band structure is investigated by numerical calculations and theoretical analysis, respectively. Then, the topological edge states existing in the structure are found by calculating the dispersion relation of acoustic metamaterial supercells. Topological transmission channels for elastic waves are then designed based on these edge states to enable precise wave guidance. Furthermore, the frequency range of the topological transmission channel can be adjusted by regulating the temperature, thereby achieving non-contact active regulation of the topological transmission frequency. This study may provide a feasible solution to realize elastic wave modulation by using topological states.