A many-body interatomic potential for ionic systems: application to MgO

TL;DR

This paper introduces a new analytic interatomic potential for ionic systems that adapts to environmental changes, enabling accurate modeling of MgO's physical properties with high efficiency.

Contribution

The paper presents a novel, efficient analytic potential that accounts for ion size and shape variability, calibrated to DFT data for MgO.

Findings

Accurately reproduces MgO potential energy surface

Matches experimental phonon frequencies

Predicts temperature and pressure effects effectively

Abstract

An analytic representation of the short-range repulsion energy in ionic systems is described that allows for the fact that ions may change their size and shape depending on their environment. This function is extremely efficient to evaluate relative to previous methods of modeling the same physical effects. Using a well-defined parametrization procedure we have obtained parameter sets for this energy function that reproduce closely the density functional theory potential energy surface of bulk MgO. We show how excellent agreement can be obtained with experimental measurements of phonon frequencies and temperature and pressure dependences of the density by using this effective potential in conjunction with ab initio parametrization.