Three-Dimensional Topological States of Phonons with Tunable Pseudospin Physics
(a) Dispersion curves of a type-II phononic TI. Blue (red) color is used to denote the contribution of I (O) vibrational modes. (b) LDOS of the (001) surface, where higher (lower) LDOS are colored red (blue). (c) Schematic phonon dispersion and pseudospin textures in the plane near . The right panel displays pseudospin textures of O (top) and I (bottom) vibrational modes from the top view.