Electric field effects on the isotropic to ferroelectric nematic phase transition

The experimental results show that the isotropic to ferroelectric nematic phase transition line ends at a critical point under an electric field. In this research, the electric field effects on the isotropic – ferroelectric nematic liquid crystal phase transition have been studied within the Landau mean-field theory. The Landau free energy is constructed as a function of the orientational order parameter and spontaneous polarization. The critical values of the electric field, transition temperature and order parameters are derived. Different topological phase diagrams have been presented to describe the boundary between phases, limit of stability, and critical point of the isotropic – ferroelectric nematic phase transition. Theoretical results show that the first order isotropic – ferroelectric nematic phase transition ends at a critical point which supports the experimental results.