Scanning X-ray diffraction microscopy of a 6 GHz surface acoustic wave

TL;DR

This study employs scanning X-ray diffraction microscopy to map the three-dimensional strain field of a 6 GHz surface acoustic wave on GaAs, revealing phase shifts and confirming models, advancing the characterization of high-frequency acoustic waves.

Contribution

It introduces a method for full 3D strain mapping of high-frequency surface acoustic waves, providing detailed insights beyond traditional imaging techniques.

Findings

Lattice distortions are phase-shifted perpendicular to the surface.

Measurements agree with Rayleigh wave models.

Achieved full 3D characterization 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 microcopy we directly map the locally resolved components of the three-dimensional strain field generated by a standing surface acoustic wave on GaAs with wavelength $\lambda\simeq500\,$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.