Effects of thermoelastic coupling on the propagation of surface acoustic waves

A two-step perturbation method is presented for the determination of the complex frequency shift of surface acoustic waves caused by their coupling to temperature fluctuations via the thermoelastic and thermoelectric effects. The anisotropy of the underlying piezoelectric medium and the thermal boundary conditions at surfaces and interfaces are taken into account by this approach. The method is applied to calculations of the thermoelastic attenuation of Rayleigh waves in LiNbO ₃, of surface acoustic waves (SAWs) in substrates covered by a thin film and in superlattices. The importance of the thermal boundary conditions causing the presence of thermal wave components with short penetration depths is demonstrated for quantitative calculations of the thermoelastic attenuation