Large effects of subtle electronic correlations on the energetics of vacancies in alpha-Fe

TL;DR

This study demonstrates that subtle electronic correlations significantly lower vacancy formation energies in alpha-Fe, aligning theoretical predictions with experimental data through advanced many-body calculations.

Contribution

The paper introduces the application of dynamical mean-field theory to accurately account for electronic correlations affecting vacancy energetics in alpha-Fe.

Findings

Vacancy formation energy is substantially reduced by electronic correlations.

Many-body effects increase local lattice relaxations around vacancies.

Spectral function changes explain correlation-induced energy reduction.

Abstract

We study the effect of electronic Coulomb correlations on the vacancy formation energy in paramagnetic alpha-Fe within ab initio dynamical mean-field theory. The calculated value for the formation energy is substantially lower than in standard density-functional calculations and in excellent agreement with experiment. The reduction is caused by an enhancement of electronic correlations at the nearest neighbors of the vacancy. This effect is explained by subtle changes in the corresponding spectral function of the d-electrons. The local lattice relaxations around the vacancy are substantially increased by many-body effects.