Surface patterning of ferroelectric nematic

Nishikawa et al discovered a novel LC material abbreviated DIO with highly polar nematic order[H. Nishikawa, 2017]. We report on patterned surface alignment of DIO using plasmonic metamasks [Y. Guo, Adv. Mater, 28, 2016]. The patterns include topological defects of strength  ½,  1. In the polar nematic phase, the patterns are accompanied by domains of opposite direction of polarization, as established by applying the in-plane electric field. The observation proves that the polar phase is a ferroelectric nematic N_F. The isolated  ½ disclinations in the nematic phase transform into composite defects in NF, with domain walls emanating from the disclination cores. Patterns of +1 circular defects show domain structures that depend strongly on whether the defect is of a bend or splay type, which illustrates that the domain structure is affected by the space charge associated with the spatial divergence of polarization.