Electronic structure and polaronic charge distributions of Fe vacancy clusters in Fe$_{1-x}$O

TL;DR

This study investigates how Fe vacancies in Fe$_{1-x}$O alter its electronic, structural, and magnetic properties, revealing polaronic charge distributions linked to short-range correlations and the Verwey transition in magnetite.

Contribution

It provides a detailed analysis of the electronic structure of Fe$_{1-x}$O with Fe vacancies, highlighting the emergence of polaronic charge distributions and their connection to magnetite's properties.

Findings

Fe vacancies cause local modifications in structure and magnetism.

Polaronic charge distributions similar to Fe$_3$O$_4$ emerge.

Insights into short-range correlations and the Verwey transition.

Abstract

We perform a detailed study of the electronic structure of Fe$_{1-x}$O at moderate values of $x$. Our results evidence that the Fe vacancies introduce significant local modifications of the structural, electronic and magnetic features, that serve to explain the origin of the measured dependencies of the physical properties on $x$. The final properties are determined by a complex interplay of the charge demand from O, the magnetic interactions, and the charge order at the Fe sublattice. Furthermore, polaronic distributions of charge resembling those at magnetite, Fe$_3$O$_4$, emerge for the most stable defect structures. This defines a unique scenario to understand the nature of the short-range correlations in Fe$_3$O$_4$, and unveils their intimate connection to the long-range charge order developed below the Verwey transition temperature.