Acoustic Dirac degeneracy and topological phase transitions realized by rotating scatterers

TL;DR

This paper demonstrates how rotating scatterers in sonic crystals induce acoustic Dirac degeneracy and enable topological phase transitions, leading to observable edge states at interfaces between different topological phases.

Contribution

It introduces a novel method of inducing topological phase transitions in acoustic systems through scatterer rotation, providing a flexible approach to topological control.

Findings

Realization of acoustic Dirac degeneracy via scatterer rotation

Observation of topological phase transitions in sonic crystals

Detection of edge states at interfaces between topologically distinct phases

Abstract

The artificial crystals for classical waves provide a good platform to explore the topological physics proposed originally in condensed matter systems. In this paper, acoustic Dirac degeneracy is realized by simply rotating the scatterers in sonic crystals, where the degeneracy is induced accidentally by modulating the scattering strength among the scatterers during the rotation process. This gives a flexible way to create topological phase transition in acoustic systems. Edge states are further observed along the interface separating two topologically distinct gapped sonic crystals.