Topological Interface States of Shear Horizontal Guided Wave in One-Dimensional Phononic Quasicrystal Slabs

In this Letter, the topological interface states of shear horizontal guided wave are investigated in a one-dimension (1D) phononic quasicrystal system. It has been found that multiple interface modes can occur at the interface of two Fibonacci sequences slabs. The occurrence of the interface states is determined by the condition that the sum of the left and right surface impedances of the interface is equal to zero. Most significantly, as the generation number of the Fibonacci sequence increases, more interface states will come into being at the interface of the quasi-periodic slabs, which is caused by the accumulation of the detuning. This study of the topological interface states in phononic quasicrystals will greatly enrich the knowledge on the topology and broaden its application scopes.