Strain dependence of the Bloch domain component in 180$^\circ$ domains in bulk PbTiO$_{3}$ from first-principles

TL;DR

This study uses first-principles simulations to explore how mechanical strain influences the emergence and stability of Bloch-type polarization components in ferroelectric domain walls in PbTiO₃, revealing strain-tunable chiral structures.

Contribution

It provides the first detailed analysis of strain effects on Bloch domain components in PbTiO₃ using density functional theory, highlighting their tunability and energetic stabilization.

Findings

Tensile strain enhances Bloch component amplitude.

Energy stabilization up to 10.7 mJ/m² due to strain.

Flat energy landscape indicates high tunability.

Abstract

We investigate the emergence of Bloch-type polarization components in 180$^\circ$ ferroelectric domain walls in bulk PbTiO$_{3}$ under varying mechanical boundary conditions, using first-principles simulations based on density functional theory. A spontaneous Bloch component$-$primarily associated with Pb displacements confined within the PbO domain wall plane$-$condense under realistic strain conditions on top of the Ising-type domain walls. The amplitude and energetic stabilization of this component are highly sensitive to the in-plane lattice parameters. In particular, tensile strains akin to those imposed by DyScO$_{3}$ substrates enhance the Bloch component and lead to energy reductions as large as 10.7 mJ/m$^{2}$ (10.6 meV/$\square$) with respect to the most stable structure including only Ising and N\'eel components. We identify a relatively flat energy landscape for the Bloch polarization, highlighting the tunability of chiral textures through strain engineering. Our results offer a predictive framework for estimating the strain-dependent onset temperature of Bloch-type domain wall components and provide insight into the design of topologically nontrivial and chiral polar structures in ferroelectrics.