Ferroelectric nematic liquid-crystal phases of dipolar hard ellipsoids

A search for ferroelectric nematic liquid crystals is carried out on the basis of a simple theoretical model viewing the nonspherical polar molecules as hard ellipsoids of revolution with an embedded permanent dipole oriented along the symmetry axis. The density-dipole moment-aspect ratio phase diagram of the dipolar hard ellipsoids has been determined with the aid of an approximate density-functional theory that was shown recently to lead to good quantitative agreement with the computer simulations of the isotropic-nematic transition of hard ellipsoids. For the dipolar hard ellipsoids, two types of stable ferroelectric nematic phases are found for dipole moments and aspect ratios exceeding some reasonable threshold values.