Polarization of thin films of barium-strontium titanate under external electric field

TL;DR

This paper develops a Landau theory model for Ba0.8Sr0.2TiO3 thin films under external electric fields, incorporating interfacial effects to explain polarization behavior and phase diagrams.

Contribution

It introduces a theoretical framework including interfacial van-der-Waals fields to analyze polarization and phase transitions in ferroelectric thin films.

Findings

Interfacial van-der-Waals field significantly influences polarization.

Constructed Ez-misfit strain phase diagram for the film.

Model explains experimental polarization behavior.

Abstract

The Landau theory of phase transitions of Ba0.8Sr0.2TiO3 thin film under external electric field applied in the planar geometry is developed. The interfacial van-der-Waals field Ez=1.1x10^8 V/m oriented normal to the film-substrate interface was introduced in to the model calculation to explain experimentally observed behavior of the polarization as a function of planar electric field. The Ez - misfit strain phase diagram of the film is constructed and discussed.