Phase behavior of the generalized chiral Lebwohl-Lasher model in bulk and confinement.

Abstract

One of the simplest models that is used to study the isotropic-nematic tranition in liquid crystalline systems is the Lebwohl-Lasher model. Several extensions of this model further enhanced its applicability. We combine two of these extensions (a generalization and the inclusion of a chiral term) and study the phase behavior and the nature of phase transitions of the resulting generalized chiral Lebwohl-Lasher model using Monte Carlo simulations. We find that the type (and even the existence) of the transition depends on the combination of the width of the interaction potential, the strength of the chiral part of the interaction, and the geometry of the system. As well, the pitch of the cholesteric bulk phase changes on approaching the phase transition if the interaction width differs from the one of the original Lebwohl-Lasher model. Thus, we identify parameter combinations that allow one to tune the properties of the ordered phase and the nature of the order-disorder transition.