Acoustic realization of quadrupole topological insulators

Abstract

A quadrupole topological insulator, being one higher-order topological insulator with nontrivial quadrupole quantization, has been intensely investigated very recently. However, the tight-binding model proposed for such emergent topological insulators demands both positive and negative hopping coefficients, which imposes an obstacle in practical realizations. Here we introduce a feasible approach to design the sign of hopping in acoustics, and construct the first acoustic quadrupole topological insulator that stringently emulates the tight-binding model. The inherent hierarchy quadrupole topology has been experimentally confirmed by detecting the acoustic responses at the bulk, edge and corner of the sample. Potential applications can be anticipated for the topologically robust in-gap states, such as acoustic sensing and energy trapping.

This paper was published in PRL: Phys. Rev. Lett. 124, 206601 (2020)

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Cited by in corpus (5)

• Higher-Order Weyl Semimetals
• Hybrid-order topological insulators in a phononic crystal
• Topological States in Two-Dimensional Su-Schrieffer-Heeger Models
• Corner states in second-order mechanical topological insulator
• Second-order topological insulator and fragile topology in topological circuitry simulation