Love-type waves in layered systems consisting of two cubic piezoelectric crystals

Dispersion relations of the seven partial Love-type waves (LTW7) have been found numerically for two-layer systems consisting of the class-23 cubic piezoelectric media Bi12SiO20 and Bi12GeO20, for two cases: a layer of Bi12SiO20 on a substrate of Bi12GeO20, and the reverse configuration. A few modes of LTW7 waves are shown, the first of which begins at a threshold value of khth∼5.3. The values of khth for the classical Love waves are tabulated for comparison with the LTW7 waves. “Dispersive solutions” have also been found, whose phase speeds are higher than the bulk shear wave speeds in either medium.