Surface shear wave propagation in the system of piezoelectric superlattice and additional metal layer

The theoretical and numerical study results on the existence of surface shear waves in a system of a piezoelectric superlattice (SL) and additional thin metal layer are presented. The SL is assumed to be formed by the semi-infinite repetition of two or more layers and to have the geometry which exhibits Bleustein-Gulyaev wave existence in a single surface problem. The corresponding dispersion equation is derived by the mathematical formalism of a periodic Hamiltonian system. Particularly, the computer experiments conducted for the CdS-ZnO SL with Al or Ag coating show that, in contrast to the homogeneous material, the considered system can support shear horizontal waves even if the cap layer velocity is greater than the velocities of SL components