Light-induced dynamics of liquid-crystalline droplets on the surface of iron-doped lithium niobate crystals

We investigated the effect of a photovoltaic field generated on the surface of irondoped lithium niobate crystals on sessile droplets of a ferroelectric nematic liquid crystalline and a standard nematic liquid crystalline material present on this surface. When such an assembly is illuminated with a laser beam, a wide range of dynamic phenomena are initiated. Droplets located outside the laser spot are dragged in the direction of the illuminated area, while droplets located inside the illuminated region tend to bridge each other and rearrange into tendril-like structures. In the ferroelectric nematic phase (NF), these processes take place via the formation of conical spikes evolving into jet streams, similar to the behavior of droplets of conventional dielectric liquids exposed to overcritical electric fields. However, in contrast to traditional liquids, the jet streams of the NF phase exhibit profound branching. In the nematic phase (N) of both the ferroelectric nematic and the standard nematic material, dynamic processes occur via smooth-edged continuous features typical for conventional liquids subjected to under-critical fields. The difference in dynamic behavior is attributed to the large increase of dielectric permittivity in the ferroelectric nematic phase with respect to the dielectric permittivity of the nematic phase.

Automated summary

This study investigates the effect of a photovoltaic field generated on the irondoped lithium niobate crystals surface on droplets of a ferroelectric nematic liquid crystal and a standard nematic liquid crystal material present on the surface. When illuminated with a laser beam, a wide range of dynamic phenomena occur, including the dragging of droplets outside the laser spot towards the illuminated area and the rearrangement and bridging of droplets in the illuminated region. The behavior of the droplets differs between the ferroelectric nematic phase and the nematic phase, attributed to the difference in dielectric permittivity between the two phases.