Electronic Structure and Lattice Relaxation Related to Fe in Mgo

TL;DR

This paper investigates the electronic structure and lattice relaxation of Fe impurities in MgO using advanced computational methods, emphasizing the importance of Coulomb potential adjustments and Jahn-Teller effects.

Contribution

It introduces a detailed analysis of Fe impurity states in MgO with LDA+U, highlighting the significance of potential choice and lattice relaxation effects on electronic structure.

Findings

Identification of the Fe$^{2+}$ and Fe$^{3+}$ electronic states

Observation of Jahn--Teller distortion effects

Quantitative analysis of ligand relaxation patterns

Abstract

The electronic structure of Fe impurity in MgO was calculated by the linear muffin-tin orbital--full-potential method within the conventional local-density approximation (LDA) and making use of the LDA+$U$ formalism. The importance of introducing different potentials, depending on the screened Coulomb integral $U$, is emphasized for obtaining a physically reasonable ground state of the Fe$^{2+}$ ion configuration. The symmetry lowering of the ion electrostatic field leads to the observed Jahn--Teller effect; related ligand relaxation confined to tetragonal symmetry has been optimized based on the full-potential total energy results. The electronic structure of the Fe$^{3+}$ ion is also calculated and compared with that of Fe$^{2+}$.