  Sessile droplets of a ferroelectric nematic liquid crystalline material were
exposed to surface electric fields produced by pyroelectric and photogalvanic
(photovoltaic) effects in X-cut iron-doped lithium niobate crystals. The
resulting dynamic processes were monitored by polarization optical
(video)microscopy (POM). During heating/cooling cycles, at first, the droplets
change their shape from spherical to extended ellipsoidal. Then they start to
move rapidly along the surface electric field, i.e., along the crystal's polar
axis (c-axis). During this motion, several droplets merge into running streams
(tendrils) extending towards the edges of the top surface area. Finally,
practically all liquid crystalline material is transported from the top surface
to the side surfaces of the crystal. At stabilized temperature, laser
illumination of the assembly causes dynamic processes that are localized to the
illuminated area. Also, in this case, the LC droplets merge into several
tendril-like formations that are preferentially oriented along the c-axis of
the crystal. The pattern of tendrils fluctuates with time, but it persists as
long as the illumination is present. In this case, the LC material is
transported between the central and the edge region of the illuminated area.
