Fluctuations-induced anomalous heat capacity above the smectic-A to smectic-C transition

The anomalous part of the heat capacity of smectic-A liquid crystals above the smectic-A to smectic-C phase transition temperature is calculated using Landau's fluctuation theory, by allowing a spatial variation of the tilt angle. The temperature dependence of the heat capacity above the transition is calculated first for a simple Gaussian model and found to be in good agreement with experiment. The quartic term in the Landau expansion, treated within perturbation theory, is shown to have a negligible contribution to the heat capacity.