Subwavelength Acoustic Valley-Hall Topological Insulators Using Soda Cans Honeycomb Lattices

Topological valley-contrasting physics has attracted great attention in exploring the use of the valley degree of freedom as apromising carrier of information. Recently, this concept has been extended to acoustic systems to obtain nonbackscattering soundpropagations. However, previous demonstrations are limited by the cut-of frequency of 2D waveguides and lattice-scale sizerestrictions since the topological edge states originate from Bragg interference. Here we engineer topologically valley-projected edgestates in the form of spoof surface acoustic waves that confne along the surface of a subwavelength honeycomb lattice composedof 330-mL soda cans. Te inversion symmetry is broken through injecting a certain amount of water into one of the two cansin each unit cell, which gaps the Dirac cone and ultimately leads to the topological valley-Hall phase transition. Dual-frequencyranges of the valley-projected edge states below the sound line are observed, which originate from the frst-order and second-orderresonances, respectively. Tese results have the potential to enable promising routes to design integrated acoustic devices based onvalley-contrasting physics.

Subwavelength Acoustic Valley-Hall Topological Insulators Using Soda Cans Honeycomb Lattices Articles