On the Perturbation of Bleustein–Gulyaev Waves in Piezoelectric Media

Abstract

The Bleustein–Gulyaev (BG) waves are subsonic surface waves which propagate along the surface of a piezoelectric half-space whose constituent material has a hexagonal symmetry, and which satisfies the mechanically free and electrically closed boundary condition. We give a perturbation to the material constants of the piezoelectric half-space of hexagonal symmetry, which consists of a perturbative part of the elasticity tensor, a perturbative part of the piezoelectric tensor and a perturbative part of the dielectric tensor. We will then present a first-order perturbation formula for the phase velocity of BG waves, which expresses the shift in the velocity from its comparative value for a hexagonal piezoelectric half-space, caused by those perturbative parts of the three tensors. It can be observed that only a few components of the perturbative parts of the tensors can affect the first-order perturbation of the phase velocity of BG waves.