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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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Magnetoactive Acoustic Topological Transistors
Abstract Topological field‐effect transistor is a revolutionary concept that physical fields are used to switch on and off quantum topological states of the condensed matter. Although this emerging concept has been explored in electronics, how to realize it in the acoustic realm remains elusive. In this work, a class of magnetoactive acoustic topological transistors capable of on‐demand switching on and off topological states and reconfiguring topological edges with external magnetic fields is presented. The key mechanism is to harness magnetic fields to tune air‐cavity volumes within acoustic chambers, thus breaking or preserving the inversion symmetry to manifest or conceal the quantum valley Hall effect. To switch the topological transport beyond the in‐plane routes, a magneto‐tuned non‐topological band gap to allow or forbid the wave transport out‐of‐plane is harnessed. With the reversible magnetic control, on‐demand switching of topological routes to realize topological field‐effect waveguides and wave regulators is demonstrated. Analogous to the impact of semiconductor transistors on modern electronics, this work may expand the scope of topological acoustics by achieving unprecedented functions in acoustic modulation.
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- Award ID(s):
- 1943598
- PAR ID:
- 10368164
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Science
- Volume:
- 9
- Issue:
- 18
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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