Tunable Locally Resonant Surface-Acoustic-Waveguiding Behavior by Acoustoelectric Interaction in ZnO-Based Phononic Crystal

The authors consider the guiding of surface acoustic waves by the local resonance band gap of a ZnO pillar-based phononic crystal, by introducing a hollow-cylindrical linear defect. Such a defect can be structurally engineered to yield narrow-band guiding modes near the middle of the gap. Moreover, the authors point out the frequency tunability of this waveguiding behavior, thanks to the acoustoelectric response of ZnO to ultraviolet illumination. This approach is attractive for designing reconfigurable, high-Q surface-acoustic-wave devices, such as filters and duplexers for wireless communication.