FullyAb InitioFinite-Size Corrections for Charged-Defect Supercell Calculations

Concepts

Natural SciencesMaterials ScienceComputational Materials ScienceCondensed Matter PhysicsSemiconductor MaterialsAb Initio MethodsDefect ModelingDefects In Electronic MaterialsDielectricsSemiconductor DefectsSemiconductor PhysicsAb Initio CalculationsAb Initio SimulationsConvergenceDefect CalculationsDiamond SemiconductorsPeriodic Boundary ConditionsSupercellsVacancies

TL;DR

Defect calculations in ab initio theory use periodic supercells, but charged defects suffer artificial interactions and no general correction scheme exists. The authors propose a new, computationally efficient method to correct charged‑defect supercell calculations, grounded in rigorous electrostatics. The method employs a rigorous electrostatic analysis in dielectric media to efficiently correct finite‑size effects. Its reliability and rapid convergence with respect to cell size are demonstrated for charged vacancies in diamond and GaAs.

Abstract

In ab initio theory, defects are routinely modeled by supercells with periodic boundary conditions. Unfortunately, the supercell approximation introduces artificial interactions between charged defects. Despite numerous attempts, a general scheme to correct for these is not yet available. We propose a new and computationally efficient method that overcomes limitations of previous schemes and is based on a rigorous analysis of electrostatics in dielectric media. Its reliability and rapid convergence with respect to cell size is demonstrated for charged vacancies in diamond and GaAs.