Fig. 3
Structural defect and internal piezoelectric response. a SEM image of model structural defect, an etched pit, located at the center of the SAW beam waist. b, c Simulated depth cross-section of the longitudinal lattice curvature and electric field magnitude (E2) in the SiC substrate. The finite element models are computed using COMSOL Multiphysics and show a time slice during continuous RF excitation of the SAW. Although the etch pit is located at a node in longitudinal curvature, increased strain and piezoelectric effects happen at the pit’s base and corners. d Enhanced dynamic piezoelectric effects at the pit are independently and all-optically mapped by native quantum defects using Electrometry by Optical Charge Conversion37, which is sensitive to the local E2. Peaks of signal are visible at the longitudinal pit edges, and the background is from stray electric fields (see Supplementary Fig. 4 for depth dependence of PL contrast)
