Propagation of Rayleigh-type surface waves in a layered piezoelectric nanostructure with surface effects

This work investigates the dispersion properties of Rayleigh-type surface waves propagating in a layered piezoelectric nanostructure composed of a piezoelectric nanofilm over an elastic substrate. As one of the most important features of nanostructures, surface effects characterized by surface stresses and surface electric displacements are taken into account through the surface piezoelectricity theory and the nonclassical mechanical and electrical boundary conditions. Concrete expressions of the dispersion equation are derived, and numerical results are provided to examine the effects of several surface-related parameters, including the surface elasticity, surface piezoelectricity, surface dielectricity, surface density, as well as surface residual stress, on the dispersion modes and phase velocity. The size-dependent dispersion behaviors occurring with surface effects are also predicted, and they may vanish once the thickness of the piezoelectric nanofilm reaches a critical value.