An acoustic black hole metaplate with magnetically tunable topological edge states

Plate-type topological acoustic black holes (ABHs) possess potential for practical applications due to their outstanding wave manipulation capabilities, which combine topological edge states with broadband energy localization. However, studies on actively controllable topological ABH plates that can adapt to different operating environments remain scarce. In this study, we present an ABH metaplate whose topological edge states can be tuned by an external magnetic field. The unit cell of the metaplate consists of a thin square ABH plate and four resonators mounted on it. These resonators include two types, with stiffnesses dependent on the applied magnetic field. Consequently, spatial symmetry breaking can be introduced by adjusting the magnetic field, thereby driving a topological phase transition in the system. We calculated the band structure of the ABH metaplate using reconstructed Gaussian basis functions. The validity of the theoretical model was verified by numerical simulation. The projected band diagrams reveal the existence of topological edge states. In a finite-sized plate, straight, Z-shaped, and l -shaped topological edge states were demonstrated, and their robustness against defects was further examined. This study opens new possibilities for the active control of topological ABH plates.