Short-circuit boundary conditions in ferroelectric PbTiO$_3$ thin films

TL;DR

This paper investigates how short-circuit boundary conditions affect density functional theory simulations of ferroelectric PbTiO$_3$ thin films with different electrode geometries, clarifying modeling approaches for ferroelectric thin films.

Contribution

It demonstrates the equivalence of boundary conditions in different supercell geometries for ferroelectric thin films with electrodes, aiding accurate modeling of ferroelectric properties.

Findings

Short-circuit conditions are satisfied in both superlattice and metal/vacuum geometries.

Different geometries offer specific advantages for studying ferroelectricity.

The study clarifies modeling approaches for ferroelectric thin films with electrodes.

Abstract

We examine the application of short-circuit electrical boundary conditions in density functional theory calculations of ferroelectric thin films. Modeling PbTiO$_3$ films with Pt electrodes, we demonstrate that under periodic boundary conditions of supercells, short-circuit conditions for the electrodes are equivalently satisfied in two repeated slab geometries: a PbTiO$_3$/metal superlattice geometry and a periodic metal/PbTiO$_3$/metal/vacuum geometry, where the metal is Pt or SrRuO$_3$. We discuss the benefits of each geometry in the study of ferroelectricity in thin films.