Bandgaps in One-Dimensional Phononic Crystal Plate with A Ferroelectric Inversion Layer

We investigate theoretically the band structures of one-dimensional phononic crystal plates with a ferroelectric inversion layer. The phononic crystal structure in the form of rectangular-like periodic grooves made on both surfaces of LiNbO3 crystal plate. The effects of the inversion layer on the dispersion curves are demonstrated using the analysis of the band structures which can be calculated by the finite element method. It is found that the width and position of Lamb wave shift prominently with variation of thickness of the inversion layer. The results obtained may provide theoretical guidance for the design of high-performance acoustic devices made of phononic crystal.