Possible Isostructural Transitions in the Ferroelectric Liquid Crystals in High External Electric Fields

Two different types of isostructural transitions between two homogeneously tilted ferroelectric liquid crystalline structures are discussed. A strong biquadratic coupling between the tilt and the polarization leads to the discontinuous jump of the tilt magnitude when the electric field is increased. A strong anisotropic quadratic coupling with the electric field leads to the continuous structural transition associated with a change of the direction of the tilt.