Phase Diagrams and Domain Splitting in Thin Ferroelectric Films with Incommensurate Phases

TL;DR

This paper investigates the phase diagram and domain structures of thin ferroelectric films with incommensurate phases using Landau-Ginzburg-Devonshire theory, revealing how thickness and surface effects influence phase transitions and domain periods.

Contribution

It provides new analytical and phase-field modelling insights into the temperature and thickness dependence of incommensurate domain structures in ferroelectric thin films.

Findings

Transition temperature depends on film thickness.

Domain period varies with temperature and surface effects.

Surface and gradient energies significantly influence phase behavior.

Abstract

We studied the phase diagram of thin ferroelectric films with incommensurate phases and semiconductor properties within the framework of Landau-Ginzburg-Devonshire theory. We performed both analytical calculations and phase-field modelling of the temperature and thickness dependencies of the period of incommensurate 180 degree domain structures appeared in thin films covered with perfect electrodes. It is found that the transition temperature from the paraelectric into the incommensurate phase as well as the period of incommensurate domain structure strongly depend on film thickness, and surface and gradient energy contributions. The results may provide insight on the temperature dependence of domain structures in nanosized ferroics with inherent incommensurate phases.