Electrostatic treatment of charged interfaces in classical atomistic simulations

TL;DR

This paper develops a systematic electrostatic formalism for classical atomistic simulations of charged interfaces, enabling accurate interpretation of simulation results affected by artificial electrostatic potentials in supercells.

Contribution

It introduces a comprehensive electrostatic treatment for various boundary conditions and system complexities, improving the analysis of ionic crystal interfaces in simulations.

Findings

Correct interpretation of electrostatic effects in simulations of ionic interfaces.

Application to SrTiO3 supercell with grain boundary shows impact on defect energies.

Enhanced understanding of charged defect behavior at interfaces.

Abstract

Artificial electrostatic potentials can be present in supercells constructed for atomistic simulations of surfaces and interfaces in ionic crystals. Treating the ions as point charges, we systematically derive an electrostatic formalism for model systems of increasing complexity, both neutral and charged, and with either open or periodic boundary conditions. This allows to correctly interpret results of classical atomistic simulations which are directly affected by the appearance of these potentials. We demonstrate our approach at the example of a strontium titanite (SrTiO$_3$) supercell containing an asymmetric tilt grain boundary. The formation energies of charged oxygen vacancies and the relaxed interface structure are calculated based on an interatomic rigid-ion potential, and the results are analyzed in consideration of the electrostatic effects.