Fig. 4. Extracting the defect interaction potential.

a Vortex core positions (symbols) with respect to the position of the closest adsorbate, differently colored for the two types of adsorbates. Targeted path (dashed line) reveals that pinning is mostly offset perpendicular to the target path. b Simulation of the vortex core path (red circles) within the displayed interaction potential (color map) that superposes the same pinning potential as displayed in c centered at each adsorbate. Adsorbate positions are taken from topography (Fig. 1f, white box). Experimental core positions (blue points, Fig. 1f) and target core positions (red crosses) are added. c The optimized, axially symmetric single defect potential consisting of an attractive part due to absent exchange energy (Fig. 3g) and a repelling Gaussian part. The three relevant fit parameters are marked.