Topological robust transmission of elastic waves in heterogeneous phononic crystal plates

Topological insulators possessing robust transmissions in the topologically protected edge have attract increasing attention. Conventionally, the topological edge states are highly concentrated at the edge with limited width, putting restrictions on the potential phononic applications. In this work, a broadened topological interface is reported in the phononic crystal plate with Y-shaped perforated holes, by adding a phononic crystal featuring Dirac points between two phononic crystals with different phases. The band structure of topological edge state together with typical displacement field is presented. Using a line source to excite on the left side of the topological interface, the topological transports of elastic waves are visualized within a broadband frequency range. Moreover, based on the broadened interface including multiple cavities at different spatial locations, the robust wave propagation is investigated by displacement fields. These results give a straightforward platform to explore the elastic wave manipulation in heterostructures for versatile advanced phononic devices.