Observation of topological valley transport of sound in sonic crystals

By Jiuyang Lu, Chunyin Qiu, Liping Ye, Xiying Fan, M. Ke, Fan Zhang, Zhengyou Liu. Nature Physics, 2016

882 citations recorded by the source corpus.

Valleytronics — exploiting a system’s pseudospin degree of freedom — is being increasingly explored in sonic crystals. Now, valley transport of sound is reported for a macroscopic triangular-lattice array of rod-like scatterers in a 2D air waveguide. The concept of valley pseudospin, labelling quantum states of energy extrema in momentum space, is attracting attention1,2,3,4,5,6,7,8,9,10,11,12,13 because of its potential as a new type of information carrier. Compared with the non-topological bulk valley transport, realized soon after predictions1,2,3,4,5, topological valley transport in domain walls6,7,8,9,10,11,12,13 is extremely challenging owing to the inter-valley scattering inevitably induced by atomic-scale imperfections—but an electronic signature was recently observed in bilayer graphene12,13. Here, we report the experimental observation of topological valley transport of sound in sonic crystals. The macroscopic nature of sonic crystals permits a flexible and accurate design of domain walls. In addition to a direct visualization of the valley-selective edge modes through spatial scanning of the sound field, reflection immunity is observed in sharply curved interfaces. The topologically protected interface transport of sound, strikingly different from that in traditional sound waveguides14,15, may serve as the basis for designing devices with unconventional functions.

Subfields: Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/d96a7e8320a13ffde52a6668b3acfa0454acedf8

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In Atomic and Molecular Physics, and Optics

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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].”
Topological phases in acoustic and mechanical systems (2019, background): “As a result, topological transport phenomena, such as one-way interface modes, are observed in the interface system constructed by two phononic crystals with opposite rotational angles for the triangular rods 96 .”
Topological acoustics (2022, neutral): “Panel m adapted from ref.(50), Springer”