1 research outputs found
Modeling Dipolar and Quadrupolar Defect Structures generated by Chiral Islands in Freely-Suspended Liquid Crystal Films
We report a detailed theoretical analysis of novel quadrupolar interactions
observed between islands, which are disk-like inclusions of extra layers,
floating in thin, freely suspended smectic C liquid crystal films. Strong
tangential anchoring at the island boundaries result in a strength +1 chiral
defect in each island and a companion -1 defect in the film, these forming a
topological dipole. While islands of the same handedness form linear chains
with the topological dipoles pointing in the same direction, as reported in the
literature, islands with different handedness form compact quadrupolar
structures with the associated dipoles pointing in opposite directions. The
interaction between such heterochiral island--defect pairs is complex, with the
defects moving to minimize the director field distortion as the distance
between the islands changes. The details of the inter-island potential and the
trajectories of the -1 defects depend strongly on the elastic anisotropy of the
liquid crystal, which can be modified in the experiments by varying the
material chirality of the liquid crystal. A Landau model that describes the
energetics of freely mobile defects is solved numerically to find equilibrium
configurations for a wide range of parameters.Comment: 8 pages, 9 figure