Fig. 5: Linearly polarized and topologically protected edge state between two phononic crystals.
From: Robust separation of topological in-plane and out-of-plane waves in a phononic crystal
a, b, c Schematics of (a) domain wall S01S10, (b) domain wall S01S11, and (c) domain wall S11S10, and their band diagrams. Ideal valley Chern numbers and their difference for in-plane polarized (IPP) [out-of-plane polarized (OPP)] wave are written in blue[red] color. The solid blue(red) line in the band diagram corresponds to the IPP(OPP) edge state of the domain wall, and the light-blue(light-red) area corresponds to the bulk band of the phononic crystals. The dotted blue(red) line in the diagram corresponds to IPP(OPP) edge state for the domain wall S10S01 for (a), S11S01 for (b), and S10S11 for (c). Linear polarization of each edge states are presented in Supplementary Fig. 10.
