Scanning X-Ray Diffraction Microscopy of a 6-GHz Surface Acoustic Wave

Abstract

Surface acoustic waves at frequencies beyond a few GHz are promising components for quantum technology applications. Applying scanning x-ray diffraction microscopy we directly map with a high lateral spatial resolution the complete strain field generated near the $\mathrm{Ga}\mathrm{As}$ surface by a standing surface acoustic wave with wavelength $\ensuremath{\lambda}\ensuremath{\simeq}500$ nm corresponding to frequencies near 6 GHz. We find that the lattice distortions perpendicular to the surface are phase shifted compared to those in propagation direction. Model calculations based on Rayleigh waves confirm our measurements. Our results represent a break through in providing a full characterization of a radio-frequency surface acoustic wave beyond plain imaging.