Structures and transitions in thin hybrid nematic films: a Monte Carlo study

We confirm by Monte Carlo simulations of a Lebwohl-Lasher lattice spin model the existence of a biaxially ordered nonbent structure in a liquid-crystalline cell subject to opposing boundary conditions. We report on the observation of the bending transition from the biaxial to the bent-director structure when the temperature of the system is lowered. The structural transition is monitored both by the change of the order parameters and by heat capacity. We discuss the thickness dependence of the transition temperature by means of wetting-induced phenomena and elastic deformations. We propose the correspondence to the phenomenological description, which agrees well without any fitting parameters.