Subwavelength Acoustic Valley-Hall Topological Insulators Using Soda Cans Honeycomb Lattices
(a) Schematic of the honeycomb lattice consisting of soda cans with basis vectors and . (b) Schematic of the unit cell in the simulations. (c) Dispersion relations of PnC without/with perturbation. Right panel: zoom in band diagram near the frequency of the first-order resonance and the second-order resonance. ,,, and denote four valley states at K point correspondingly. Gray circles and red dots represent the situations with and 0.2 cm, respectively. Blue dashed line represents the sound line. (d) Eigenmodes of four valley states. Colors represent total pressure fields and the black cones show the direction and amplitude of the intensity.