Acoustic surface-guided modes in phononic crystals

We study theoretically and experimentally the nature of formation and properties of acoustic surface-guided modes (SGMs) at the interface of two phononic crystals (PCs). It is demonstrated that in the shared region of the frequency gaps, the SGMs can exist at the interface as a result of total reflections from both PCs, which causes the formation of nodal planes by the interference of the forward- and backward-propagating waves. The experiments show excellent agreement with the theory predictions