Acoustic topological insulator and robust one-way sound transport

By Cheng He, Xu Ni, Hao Ge, Xiao‐Chen Sun, Yan‐Bin Chen, Ming-Hui Lu, Xiao-Ping Liu, Yan-Feng Chen. Nature Physics, 2015

1,105 citations recorded by the source corpus.

The acoustic analogue of a topological insulator is shown: a metamaterial exhibiting one-way sound transport along its edge. The system — a graphene-like array of stainless-steel rods — is a promising new platform for exploring topological phenomena. Topological design of materials enables topological symmetries and facilitates unique backscattering-immune wave transport1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26. In airborne acoustics, however, the intrinsic longitudinal nature of sound polarization makes the use of the conventional spin–orbital interaction mechanism impossible for achieving band inversion. The topological gauge flux is then typically introduced with a moving background in theoretical models19,20,21,22. Its practical implementation is a serious challenge, though, due to inherent dynamic instabilities and noise. Here we realize the inversion of acoustic energy bands at a double Dirac cone15,27,28 and provide an experimental demonstration of an acoustic topological insulator. By manipulating the hopping interaction of neighbouring ’atoms’ in this new topological material, we successfully demonstrate the acoustic quantum spin Hall effect, characterized by robust pseudospin-dependent one-way edge sound transport. Our results are promising for the exploration of new routes for experimentally studying topological phenomena and related applications, for example, sound-noise reduction.

Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/8279d4cc0288f6a0f805588b54331528b436328a

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Citations in the corpus

Observation of second-order topological insulators in sonic crystals (2018, background): “These gapless edge states are dictated by the topological invariants associated with the quantization of generalized Berry’s phases of the bulk energy bands through the bulk-edge correspondence, a paradigm that can also be extended to acoustic and photonic systems [5-23].”
Artificial gauge fields in materials and engineered systems (2017, positive): “Models associated with topological Bloch bands have been studied with an array of coupled mechanical pendula [196] and in a honeycomb lattice of metallic cylinders [211]; see also the proposal [194].”
Topological acoustics (2022, background): “Acoustic systems: 1D topological phase [81], quantum spin Hall insulator [39], Floquet topological insulator [155], valley Hall insulator [53], Weyl crystal [120, 121], 1D non-Hermitian topological pump [170], quantum Hall insulator [30], 2D second-order topological insulator [90–92], 3D third-order”
Active times for acoustic metamaterials (2019, background): “supports spin-polarized protected edge modes [156].”
Edge waves in plates with resonators: an elastic analogue of the quantum valley Hall effect (2016, background): “Khanikaev et al [20] conducted numerical studies onwave propagation in a plate having 2-scale perforations, while Chen and coworkers [21] achieved OPEN ACCESS”
Topological Phases of Non-Hermitian Systems (2018, neutral): “[39] Cheng He, Xu Ni, Hao Ge, Xiao-Chen Sun, Yan-Bin Chen, Ming-Hui Lu, Xiao-Ping Liu, and Yan-Feng Chen, “Acoustic topological insulator and robust one-way sound transport,” Nat.”