Monte Carlo simulations of biaxial ordering in systems of uniaxially interacting rodlike ellipsoids

The minimal ingredient to generate a biaxial liquid-crystalline order is usually considered to be a strong biaxiality either in the molecular shape or in the molecular interactions. Although there is no fundamental reason to forbid a spontaneous biaxial liquid-crystalline ordering of pure uniaxial origin, a robust demonstration of such phenomenon has been a challenging problem. We report here off-lattice Monte Carlo simulations of some new model systems of polar achiral rodlike ellipsoids which spontaneously form biaxial smectic phases of pure uniaxial origin. The phases also exhibit fascinating ferroelectric or striped ordering of the dipolar ellipsoids. We demonstrate that suitably tuned dipolar interactions can play major roles in generating biaxial phases of uniaxial origin for a wide variety of molecular length-to-width ratios.