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.

Wave Manipulation in Intelligent Metamaterials: Recent Progress and Prospects

“…Using external magnetic loads, Lee et al [85] proposed a novel magnetoactive acoustic topological transistors (MATTs), achieving on-demand switching of topological interface states. This kind of MATTs enables the reconfiguration of acoustic conductive routes both in-plane and out-of-plane.…”

Tunable, reconfigurable, and programmable acoustic metasurfaces: A review

“…In general, the use of magnetoactive materials and temperature changes has been proposed as a solution. These have conspicuous advantages like low-frequency wave manipulation (Chen et al, 2014;Chen et al, 2017;Liu et al, 2020), switching on and off of topological states (Lee et al, 2022), and production of negative modulus and density (Xia et al, 2016) which leads to the acquisition of a wider acoustic band, better adjustability, and more balanced performance.…”

“…This property can be leveraged to design structures that undergo a certain geometric change by modulation of the applied field. The mechanics of magnetic control is classified into two subcategories of single and multifilm structures, with multi-film magnetic AMs exhibiting better performance and a wider bandwidth with regard to sound insulation (Yu et al, 2018;Lee et al, 2020;Lee et al, 2022;Xia et al, 2022). To exemplify, Lee et al (2022) proposed a class of magnetoactive acoustic topological transistors capable of switching topological states on and off and reconfiguring topological edges on-demand with external magnetic fields.…”

“…The mechanics of magnetic control is classified into two subcategories of single and multifilm structures, with multi-film magnetic AMs exhibiting better performance and a wider bandwidth with regard to sound insulation (Yu et al, 2018;Lee et al, 2020;Lee et al, 2022;Xia et al, 2022). To exemplify, Lee et al (2022) proposed a class of magnetoactive acoustic topological transistors capable of switching topological states on and off and reconfiguring topological edges on-demand with external magnetic fields. As presented in Figure 5A, a class of active metamaterials was inspired by shark skin denticles whose configuration can be switched on demand by untethered magnetic fields to enable wave guiding, reciprocity, and logic operation (Lee et al, 2020).…”

Self-powered non-reciprocal phononic logic gates

“…The acoustic diodes by the non-reciprocal propagation of acoustic waves were achieved by breaking the spatial inversion symmetry 5 , dynamic boundary conditions 6 , effect of radiation pressure 7 , media with nonlinear dynamical properties 8,9 and breaking the time-reversal symmetry 10,11 . The acoustic transistors were studied by introducing the magnetic eld adjustment 12,13 or cascade structure 14 , which provide the basis for complex acoustic logic operations together with the acoustic diodes. Based on acoustic diodes and transistors, the acoustic logic gates were realized by multi-port curved waveguide 15,16 , near-zero density acoustic metamaterial 17 , spherical particle acoustic switch 18 , passive Parity-Time symmetry metamaterials 19 , programmable acoustic topological insulator 20 and binary-phase passive unit cells 21 .…”