Robust elastic shear wave transport in membrane-type topological metamaterials induced by material difference

Abstract

Novel membrane-type topological metamaterials induced by material difference are investigated in this work. Different from previous common method to break spatial inversion symmetry and realize topological phase transition, choosing different materials is more convenient and shows more complex topological properties. Not all combinations of different materials can open the topological band gap. Interestingly, not only the topological interface modes but also the conventional interface modes are found in this system. Although strong energy localization capacity is found near the interface, both kinds of interface modes show different robustness against defects. To further enhance adaptability to environmental variations and broaden the working frequency range, the thermal field is introduced in membrane-type topological metamaterials to tune the dispersion relations. Fortunately, not only interface modes can be tuned to a lower frequency range, but also the energy localization of interface modes can be remained at a high level. The temperature can act as a switch to turn on/off the robust shear wave transport in membrane-type topological metamaterials. Given that, novel temperature-controlled topological metamaterials are expected to open new avenues for active elastic multifunctional devices.