Transverse acoustic waves in piezoelectric and ferroelectric antiphase superlattices

The diffraction of a shear horizontally polarized acoustic wave is analyzed at an oblique incidence upon the superlattice, which describes a system of 180 degrees ferroelectric domains or a stack of antiparallel piezoelectric layers. The formalism of 4x4 propagator-matrix formalism, which takes into account the electromechanical coupling, is pursued. The developed algebrai c procedure provides a comprehensive analytical description of the reflecti on and transmission rates in an explicit and concise form. This allows dire ct examination of the resonant features of the reflection and transmission spectra at an unrestricted variation of the involved parameters. In the cas e of nonequidistant superlattices, the modulation of the Bragg peaks is cha racterized and the extinction rule deduced. [S0163-1829(99)08113-8].