6 research outputs found
Theory and simulation of the confined Lebwohl-Lasher model
We discuss the Lebwohl-Lasher model of nematic liquid crystals in a confined
geometry, using Monte Carlo simulation and mean-field theory. A film of
material is sandwiched between two planar, parallel plates that couple to the
adjacent spins via a surface strength . We consider the cases where
the favoured alignments at the two walls are the same (symmetric cell) or
different (asymmetric or hybrid cell). In the latter case, we demonstrate the
existence of a {\it single} phase transition in the slab for all values of the
cell thickness. This transition has been observed before in the regime of
narrow cells, where the two structures involved correspond to different
arrangements of the nematic director. By studying wider cells, we show that the
transition is in fact the usual isotropic-to-nematic (capillary) transition
under confinement in the case of antagonistic surface forces. We show results
for a wide range of values of film thickness, and discuss the phenomenology
using a mean-field model.Comment: 40 pages 19 figures (preprint format). Part of the text and some
figures were modified. New figure was include