Subwavelength Acoustic Valley-Hall Topological Insulators Using Soda Cans Honeycomb Lattices
(a) Band inversions between and states induced by the 1st-order resonance with changing the perturbation from 0.2 cm to 0.2 cm. (b) Eigenfrequency evolution of the valley states / depending on at the K point. (c)-(d) Same as (a)-(b) but of the valley states and induced by the 2nd-order resonance. The cyan and yellow regions show two different valley-Hall phases, labeled as I and II.