Ab initio based study on atomic ordering in {(Ba, Sr)}TiO$_3$

TL;DR

This study uses ab initio methods to explore how atomic ordering and Sr concentration affect the structural and ferroelectric properties of (Ba, Sr)TiO$_3$, revealing significant impacts on Curie temperature and polarization.

Contribution

It provides new insights into the influence of atomic ordering on ferroelectric phase stability and properties in (Ba, Sr)TiO$_3$ using combined DFT and molecular dynamics.

Findings

Curie temperature varies by 9% with Sr distribution symmetry.

Polarization differs by 17% depending on Sr ordering.

Local Sr ordering affects ferroelectric phase stability.

Abstract

\ We combine density functional theory and molecular dynamics simulations to investigate the impact of Sr concentration and atomic ordering on the structural and ferroelectric properties of (Ba, Sr)TiO$_3$. On one hand, the macroscopic structural properties are rather insensitive to atomic ordering. On the other hand, the Curie temperature and polarization differ by $9$\% and $17$\% for different symmetries of the Sr distribution, respectively. Local ordering of Sr induces preferential polarization directions and influences the relative stability of the three ferroelectric phases.