Research: Surface acoustic waves
The linear electromechanical coupling in piezoelectric materials enables the interconversion between electrical and acoustic signals, which has found numerous applications in modern science and technology. Here the characteristic dimension is set by the wavelength of surface acoustic wave (SAW) in piezoelectric solids, which is 5 orders of magnitude smaller than the electromagnetic wavelength at the same frequency. Research work that provides spatial information in the mesoscopic length scale is therefore highly desirable for studying the interference, diffraction, and localization of supersonic SAWs.
L. Zheng et al. PNAS 115, 5338 (2018)
Piezoelectric transduction maps in LiNbO3 corral domains shaped in triangle, hexagon, circle, and square, showing clear interference patterns due to the superposition of ripples around each domain wall. (Top: PFM images; Middle: MIM-Re images; Bottom: artistic rendering of the MIM data)
L. Zheng et al. Phy. Rev. Applied 9, 061002 (2018)
SAW on ferroelectric samples can be visualized by transmission-mode microwave impedance microscopy (T-MIM). Left: The SAW potential launched by the interdigital transducer is detected by the tip, showing the wave-like patterns on the LiNbO3 surface. Right: Schematic of the setup and wave diffraction due to a small domain with opposite polarization.
This research is funded by the NSF Grant DMR-1707372.