Transition of frustrated nematic order and fluctuation of topological defects in microwrinkle grooves

We show that a nematic liquid crystal confined in sinusoidal microwrinkle grooves imposing antagonistic boundary conditions exhibits noteworthy structural transitions of nematic order and associated line defects under the variation of temperature (T). The defects also show unusual temperature-dependent fluctuations whose amplitude squared depends nonlinearly on T. The temperature dependence of the elastic constants of the liquid crystal and their ratio is responsible for these transitions and fluctuations. A variety of transformable defect structures with characteristic fluctuations will open up new possibilities for organizing and manipulating colloids and a liquid crystal confined in microwrinkle grooves could be a tangible one-dimensional model system to study the nature of fluctuations.