Fig. 1: Parabolic domain walls in N_F films of DIO.

a Polarizing microscopy texture of two P-walls with foci at the cores of circular +1 vortices; the average film thickness h ≈ 4.8 μm; note two “ghost” parabolas extending to the upper left corner. b The corresponding eccentricities e. c The corresponding eccentricities e and distances d to directrices as fits to Eq. (1). d PolScope Microimager texture of a P-wall separating a vortex P₂ from a nearly uniform P₁; the tip of the P-wall is replaced by a T-wall, ending at two −1/2 disclinations; the yellow pseudo color of the T-wall is an artifact of Microimager since the actual retardance is in the lower interference order as compared to the rest of the texture; h ≈ 4.1 μm. e, f The corresponding e’s, d’s, and fits to Eq. (1). g A P-wall responds differently to the opposite polarities (h, i) of a dc electric field, which allows one to deduce the polarization pattern. Source data for (b, e) are provided as a Source Data file. The error bars in (c) represent the instrumental error in measuring the coordinates of the defects.