Lattice model for the tricritical point of the nematic–smectic-A phase transition

We present a lattice model for the nematic–smectic-A phase transition in liquid crystals. It reduces to the de Gennes model in the continuum limit and, in contrast to earlier lattice attempts, is capable of describing the phase transition in both the second- and first-order regimes, thus comprising also the experimentally observed tricritical point. The model is investigated using mean-field techniques and Monte Carlo simulations.