Domain enhanced interlayer coupling in ferroelectric/paraelectric superlattices

TL;DR

This paper studies how ferroelectric and paraelectric layers in superlattices interact, affecting phase transition temperatures and domain formations, with theoretical models aligning with experimental observations.

Contribution

It introduces a coupled electrostatic and Ginzburg-Landau model to explain interlayer interactions and transition temperature shifts in ferroelectric/paraelectric superlattices.

Findings

Polarization domains interact across layers via electrostatic coupling.

Critical temperature depends on superlattice wavelength.

Model matches experimental thickness dependence of transition temperature.

Abstract

We investigate the ferroelectric phase transition and domain formation in a periodic superlattice consisting of alternate ferroelectric (FE) and paraelectric (PE) layers of nanometric thickness. We find that the polarization domains formed in the different FE layers can interact with each other via the PE layers. By coupling the electrostatic equations with those obtained by minimizing the Ginzburg-Landau functional we calculate the critical temperature of transition Tc as a function of the FE/PE superlattice wavelength and quantitatively explain the recent experimental observation of a thickness dependence of the ferroelectric transition temperature in KTaO3/KNbO3 strained-layer superlattices.