Related papers: Ferroelectric ordering in chiral smectic C^* liqui…
Statistical theory of the dielectric susceptibility of polar liquid crystals is proposed. The molecules are calamitic or bent-core but the permanent dipole moment is perpendicular to the molecule long axis. The ordering of the phase is…
The recent discovery of ferroelectric nematics-genuine 3D ferroelectric fluids-has underscored the importance of electrostatic interactions in shaping the physical behaviour of soft matter systems. In this paper, we investigate the…
We present a theoretical model which describes the polarization modulated and layer undulated structure of the B7 phase and gives the phase transition from the synclinic ferroelectric B2 phase to the B7 phase as observed experimentally. The…
We present a detailed study of complex dielectric constant and ferroelectric polarization in multiferroic LiCuVO4 as function of temperature and external magnetic field. In zero external magnetic field, spiral spin order with an ab helix…
Ferroelectric order in polar liquids has been observed in numerical simulations and liquid-crystal experiments. In mean-field frameworks, this behavior is associated to sample-shape dependent, surface contribution to the free energy. This…
We are concerned with the modification of liquid crystalline and polar order in SmC* liquids by illumination. In particular we show that non-uniformity due to absorption and also dynamics, can be complex. The variation of polarization with…
We show that surface interactions can vectorially structure the three-dimensional polariza-tion field of a ferroelectric fluid. The contact between a ferroelectric nematic liquid crystal and a surface with in-plane polarity generates a…
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…
Strongly dipolar mesogenic compounds with a chiral center located in a lateral alkyl chain were synthesized, and shown to form the ferroelectric nematic phase. The presence of molecular chirality induced a helical structure in both the N…
Multiferroic CuFe1-xAlxO2 (x=0.02) exhibits a ferroelectric ordering accompanied by a proper helical magnetic ordering below T=7K under zero magnetic field. By polarized neutron diffraction and pyroelectric measurements, we have revealed a…
The macroscopic dielectric permittivity of dielectric crystals is related to the microscopic atomic polarizability of constituent atoms by the known Clausius-Mossotti relation obtained in the middle of 19th century. We derive a similar…
The proton ordering model for the KH$_{2}$PO$_{4}$ type ferroelectrics is modified by taking into account non-linear effects, namely, the dependence of the effective dipole moments on the proton ordering parameter. Within the four-particle…
Following the groundbreaking discovery of the ferroelectric nematic liquid crystal phase (NF), a series of closely-related new polar phases have also been found. An especially interesting one is the ferroelectric smectic A phase (SmAF) with…
A stochastic model for polarization switching in tetragonal ferroelectric ceramics is introduced, which includes sequential 90{\deg}- and parallel 180{\deg}-switching processes and accounts for the dispersion of characteristic switching…
The origin of ferroelectricity in KH_2PO_4 (KDP) is studied by first-principles electronic structure calculations. In the low-temperature phase, the collective off-center ordering of the protons is accompanied by an electronic charge…
The $\beta$ and $\gamma$ phases of methylammonium chloride CH$_3$NH$_3$Cl and methylammonium bromide CH$_3$NH$_3$Br are identified to be ferroelectric $via$ pyroelectric current and dielectric constant measurements. The magnetic…
We develop a lattice model for the splay flexoelectric effect in nematic liquid crystals. In this model, each lattice site has a spin representing the local molecular orientation, and the interaction between neighboring spins represents…
The first switchable electric polarization in metals was recently discovered in bilayer and trilayer WTe2. Strangely, despite the tininess of the ordered polarization, the ferroelectricity survives up to 350 K, rendering the mechanism of…
The Modern Theory of Polarization, which rigorously defines the spontaneous electric polarization of a periodic solid and provides a recipe for its computation in electronic structure codes, transformed our understanding of ferroelectricity…
Because of their spontaneous bulk polarization, ferroelectric nematic liquid crystals can be easily brought by surface coupling or confinement in a state in which the accumulation of bound charges becomes incompatible with polar order,…