Abstract
We propose a reconfigurable, electroacoustic topological insulator inspired by the Su-Schrieffer-Heeger (SSH) lattice and then study dynamically-switched topological interfaces. The electroacoustic unit cell design is composed of a host structure with bonded piezoelectric attachments shunted via negative capacitance circuits. We first identify topological behavior via band structure calculations associated with the unit cell. By selectively modifying the elastic properties of the repeated unit cells via attached shunted circuits, we then join two one-dimensional lattices with mirror symmetry to yield a topologically-protected interface mode. We compute the characteristic frequencies and compare the harmonic response of the structures with and without an interface to show amplitude localization at an interface for a frequency within a topological band gap. Control of the shunted circuits using electrical switches allows for reconfiguration of the structure, thereby permitting relocation of the topological interface at an arbitrary time instant. We present numerical studies simulating the diffusion of energy as the interface is shifted from one location to another, exploiting topological-protection to ensure minimal energy loss in spite of a non-smooth change in the elastic properties of the lattice. Our work demonstrates robust, movable interfaces in one-dimensional elastic media which may find applications in communication devices and acoustic tweezing.
