Effects of initial stress on band gap of Love waves in a layered domain-inverted phononic crystal structure.

Love wave propagation in periodically domain-inverted lithium niobate substrate with a homogeneous zinc oxide waveguide layer is theoretically investigated. Much attention is devoted to the effect of initial stress on the band gap and dispersion behavior of Love wave in the layered structure. The results reveal a strong dependency of the band structure on the waveguide layer. In particular, as the waveguide layer gradually thickens, the band gap shifts into a lower frequency range remarkably. Additionally, the initial stress has a significant influence on the location of the band gap, but a small effect on the bandgap width. This separate effect provides the potential to actively tune the surface acoustic waves by the stress.