First-principles study of the structural, electronic, magnetic and ferroelectric properties of a charge ordered Iron(II)- Iron(III) formate framework

TL;DR

This study uses density functional theory to analyze the structural, electronic, magnetic, and ferroelectric properties of a charge-ordered Fe(II)-Fe(III) formate framework, aligning with experimental findings and exploring mechanisms to enhance polarization.

Contribution

It provides a detailed first-principles analysis of the properties of a mixed-valence iron formate framework, revealing mechanisms behind its ferroelectric polarization and suggesting ways to improve it.

Findings

Calculated spontaneous polarization matches experimental values.

Identified microscopic mechanisms for charge and dipolar ordering.

Proposed directions to enhance ferroelectric polarization.

Abstract

Density functional theory calculations have been performed for the structural, electronic, magnetic and ferroelectric properties of a mixed-valence Fe(II)-Fe(III) formate framework [NH$_2$(CH$_3$)$_2$][Fe$^{\rm III}$Fe$^{\rm II}$(HCOO)$_6$] (DMAFeFe). Recent experiments report a spontaneous electric polarization and our calculations are in agreement with the reported experimental value. Furthermore, we shed light into the microscopic mechanism leading to the observed value and as well how to possibly enhanced the polarization. The interplay between charge ordering, dipolar ordering of DMA$^+$ cations and the induced structural distortions suggest new interesting directions to explore in these complex multifunctional hybrid perovskites.