  The realization of a spontaneous macroscopic ferroelectric order in fluids of
anisotropic mesogens is a topic of both fundamental and technological interest.
Recently, we demonstrated that a system of dipolar achiral disklike ellipsoids
can exhibit long-searched ferroelectric liquid crystalline phases of dipolar
origin. In the present work, extensive off-lattice Monte Carlo simulations are
used to investigate the phase behavior of the system under the influences of
the electrostatic boundary conditions that restrict any global polarization. We
find that the system develops strongly ferroelectric slablike domains
periodically arranged in an antiferroelectric fashion. Exploring the phase
behavior at different dipole strengths, we find existence of the ferroelectric
nematic and ferroelectric columnar order inside the domains. For higher dipole
strengths, a biaxial phase is also obtained with a similar periodic array of
ferroelectric slabs of antiparallel polarizations. We have studied the
depolarizing effects by using both the Ewald summation and the spherical
cut-off techniques. We present and compare the results of the two different
approaches of considering the depolarizing effects in this anisotropic system.
It is explicitly shown that the domain size increases with the system size as a
result of considering longer range of dipolar interactions. The system exhibits
pronounced system size effects for stronger dipolar interactions. The results
provide strong evidence to the novel understanding that the dipolar
interactions are indeed sufficient to produce long range ferroelectric order in
anisotropic fluids.
