Fig. 4: Evolving polar vortices in the depth direction.
From: Polar vortex hidden in twisted bilayers of paraelectric SrTiO3
a Depth variation of the experimental polarization distribution in a small region in the lower layer. The corresponding regions in Fig. 2f are indicated by a green square. The relative depth values are labeled on the top of each image. Scale bar, 2 nm. b Depth variation of the polarization from a phase-field simulation. Scale bar, 2 nm. The color maps of (a) and (b) stand for the vorticity in the unit of 1010 C/m3.
