Role of long-range dipolar interactions in the simulation of the properties of polar crystals using effective atomic potentials

TL;DR

This paper investigates the impact of long-range dipolar interactions on modeling polar materials, showing that neglecting these can still yield reasonable results but may introduce artifacts, guiding improvements in atomic potentials.

Contribution

It systematically compares models with and without long-range dipolar interactions in polar materials, highlighting when inclusion is necessary for accuracy.

Findings

Neglecting long-range interactions can cause artifacts in polar material simulations.

Models without long-range dipolar terms still capture overall properties reasonably well.

Guidelines are proposed for when to include long-range dipolar interactions in potentials.

Abstract

Driven by novel approaches and computational techniques, second-principles atomic potentials are nowadays at the forefront of computational materials science, enabling large-scale simulations of material properties with near-first-principles accuracy. However, their application to polar materials can be challenging, particularly when longitudinal-optical phonon modes are active on the material, as accurately modeling such systems requires incorporating the long-range part of the dipole-dipole interactions. In this study, we challenge the influence of these interactions on the properties of polar materials taking BaTiO$_3$ as paradigmatic example. By comparing models with and without the long-range part of the electrostatic contributions in a systematic way, we demonstrate that even if these interactions are neglected, the models can still provide an overall good description of the material, though they may lead to punctual significant artifacts. Our results propose a pathway to identify when an atomistic potential may be inadequate and needs to be corrected through the inclusion of the long-range part of dipolar interactions.