Ferroelectric system dynamics simulated by a second-order Landau model

Abstract

By using a second-order time-dependent Ginzburg–Landau model, we simulate the dynamic polarization hysteresis behavior of a ferroelectric system subjected to a sinusoidal electric field. We examine polarization hysteresis loop structure as a function of both field amplitude and field frequency. The relationship between the latter and hysteresis loop area, i.e., hysteresis dispersion, is calculated. Departing from previous work that established that the considered model produces experimentally expected hysteresis dispersion in the low-frequency regime, we demonstrate that (i) this model also produces experimentally expected hysteresis dispersion in the high-frequency regime; (ii) this dispersion implies, in agreement with experimental observations, that system relaxation is characterized by an effective characteristic time which is inversely proportional to field amplitude when the latter is sufficiently high; and (iii) the considered model predicts a symmetry-breaking transition that depends on both field frequency and field amplitude.

First-principles experimental demonstration of ferroelectricity in a thermotropic nematic liquid crystal: Polar domains and striking electro-optics

“…Here we show, in a previously reported thermotropic material, defining evidence for ferroelectricity and a host of emergent polar behaviors that promise to remake the science and technology of nematics. boundaries can be moved or removed by application of a field, then the mean polarization can be changed, and if this motion is irreversible, then the polar phase will exhibit switching and hysteresis as emergent properties and can be considered macroscopically ferroelectric (27). Here we present the direct observation of such spontaneously broken symmetry in the form of domains of opposite polarization, grown without applied electric field, as a firstprinciples demonstration of ferroelectricity in a thermotropic, uniaxial, nematic liquid crystal (LC) of rod-shaped molecules.…”

Dynamic Stabilization of Metastable States in Triple‐Well Ferroelectric Sn2P2S6

“…To illustrate our approach for the detection of metastable states in Sn 2 P 2 S 6 , we present the contrast between Landau–Khalatnikov models [ 13 ] for the double‐ and triple‐wells in an applied electric field (Figure 1c,e, respectively). In these models, the alternating electric field was applied with an envelope function, gradually increasing in amplitude as a function of time.…”