Surface acoustic wave ferroelectric phononic crystal tunable by electric field

Theoretical investigation results of the periodic domain structures induced by an electric field in barium strontium titanate (Ba$_{x}$Sr$_{1-x}$)TiO$_{3}$ ferroelectric thin film are presented. A novel type of tunable phononic crystal based on an electric field-induced piezoelectric effect in a thin ferroelectric film is proposed. Surface acoustic wave propagation equations for the substrate under electric field-induced periodic domains are derived. Finite element simulation revealed the possibility of applying the ferroelectric phononic crystal as an electrically tunable surface acoustic wave filter.