Stark-ladder resonances in piezoelectric composites -: art. no. 174109

In this paper we introduce a piezoelectric composite medium. The composite shows a series of resonances similar to the Stark-ladder resonances originally observed in the propagation of electrons through crystals in a dc electric field. These resonances appear when shear horizontal and surface waves propagate through a special piezoelectric composite medium consisting of N piezoelectric layers, each layer being a material of hexagonal 6mm symmetry. For periodic piezocomposites, we obtain a band structure as expected. However, when the periodicity is broken by adding a linear term in the values of the piezoelectric parameters of the layers, the band structure is destroyed and, in certain cases, resonances of Stark-ladder type appear instead. A 4x4 transfer matrix approach is used to calculate the response of the composite under electromechanical perturbations. The response is studied as a function of the properties of the different materials, width of the layers, wave frequency, and angle of incidence. Numerical results for the electric potential and for the displacement of the surface of the last layer of the composite are presented showing the existence of Stark-ladder resonances.