We propose an electroacoustic transistor enabled by reconfigurable topological insulators (TIs). The underlying structure of the device is a hexagonal lattice with a unit cell consisting of piezoelectric disks bonded to an aluminum substrate. First, we study the dispersion of flexural waves in the reconfigurable TI to identify Dirac cones in the band structure of a unit cell possessing C6v-symmetry. A topological bandgap can be opened by breaking inversion symmetry in the unit cell. This is achieved by altering the elastic response of one of the affixed piezoelectric disks using a negative impedance shunt circuit. Next, we analyze various topological states formed by interfacing mirror-symmetric unit cells. Sublattices with interface states are then combined to construct a transistor supercell which hosts at least two topologically protected channels for wave propagation. The amplitude of an incoming acoustic signal propagating in one of the topological channels, referred to as the ‘Gate’, is used to switch on or off a second topological channel between a wave source and receiver, mimicking the behavior of a field effect transistor in electronics. We employ finite element analysis to study the harmonic response of the transistor structure demonstrating the OFF and ON states of the device. Further, we present a mock-up of an electrical circuit which enables the switching of the topological channel between a wave source and receiver. The design of the proposed wave-based transistor promises the advantage of topological protection and may find applications in wearable devices, edge computing, and sensing in harsh environments.
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Experimental demonstration of an electroacoustic transistor
We experimentally demonstrate a topologically protected electroacoustic transistor. We construct a reconfigurable phononic analog of the quantum valley-Hall insulator composed of electrically shunted piezoelectric disks bonded to a patterned plate forming a monolithic structure. The device can be dynamically reconfigured to host one or more topological interface states via breaking inversion symmetry through selective powering of shunt circuits. Above a threshold, the amplitude of wave energy at a chosen location in one topological interface creates a second interface by dynamically switching power between two groups of shunts using relays. This enables the flow of wave energy between two locations in the reconfigured interface analogous to the voltage-controlled electron flow in a field effect transistor. The amplitude of wave energy in the second interface is used for bit abstraction to implement acoustic logic. We illustrate the various states of the transistor and experimentally demonstrate wave-based switching. The proposed electroacoustic transistor is envisioned to find applications in wave-based devices and edge computing in extreme environments and inspire novel technologies leveraging acoustic logic.
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- Award ID(s):
- 2242925
- PAR ID:
- 10520143
- Publisher / Repository:
- AIP
- Date Published:
- Journal Name:
- Applied Physics Letters
- Volume:
- 124
- Issue:
- 24
- ISSN:
- 0003-6951
- Page Range / eLocation ID:
- 244102-1 to 244102-7
- Subject(s) / Keyword(s):
- Topological insulator, Acoustics, Transistors, Wave power, Wave forms, Computational models
- Format(s):
- Medium: X Other: pdf
- Sponsoring Org:
- National Science Foundation
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