Monte Carlo simulations of biaxial structure in thin hybrid nematic film based upon spatially anisotropic pair potential

Hybrid nematic films have been studied by Monte Carlo simulationsusing a lattice spin model, in which the pair potential is spatiallyanisotropic and dependent on elastic constants of liquid crystals.We confirm in the thin hybrid nematic film the existence of abiaxially nonbent structure and the structure transition from thebiaxial to the bent-director structure, which is similar to theresult obtained using the Lebwohl--Lasher model. However, thestep-like director's profile, characteristic for the biaxialstructure, is spatially asymmetric in the film because the pairpotential leads to $K_1 ne K_3 $. We estimate the upper cellthickness to be 69 spin layers, in which the biaxial structure canbe found.