★ A general dispersion relation for transverse surface waves propagating in multilayered piezoelectric coupled solids is given. ★ The hard metal interlayer can get rid of the undesired mode appearing in the case without interlayer. ★ The hard metal interlayer can also shorten the wave number range for the existence of phase velocity. ★ The effects of the interlayer on phase velocity can be used to manipulate the wave behavior in acoustic wave devices.
The propagation of transverse surface waves in a piezoelectric layer/metal substrate system with one or multiple hard metal interlayer(s) is investigated analytically. The general dispersion equations for the existence of the waves are obtained in a simple mathematic form for class 6 mm piezoelectric materials. The presence of a hard metal interlayer can not only get rid of the undesired mode appearing in the case without an interlayer but shorten the existence range of the phase velocity within which a nonleaky but dispersive mode exists. The effects of the hard interlayer on the phase velocity can be used to manipulate the behavior of the waves and has implications in acoustic wave devices.