Advances in ab-initio theory of Multiferroics. Materials and mechanisms: modelling and understanding

TL;DR

This paper reviews ab-initio theoretical approaches to understanding multiferroics, especially electronic ferroelectrics driven by electronic degrees of freedom, highlighting microscopic mechanisms and material examples.

Contribution

It provides a comprehensive review of first-principles methods applied to multiferroics, emphasizing electronic mechanisms and diverse material classes.

Findings

Identification of microscopic mechanisms driving multiferroicity

Application of density functional theory to various compounds

Insights into spin-induced ferroelectricity and magnetoelectric coupling

Abstract

Within the broad class of multiferroics (compounds showing a coexistence of magnetism and ferroelectricity), we focus on the subclass of "improper electronic ferroelectrics", i.e. correlated materials where electronic degrees of freedom (such as spin, charge or orbital) drive ferroelectricity. In particular, in spin-induced ferroelectrics, there is not only a {\em coexistence} of the two intriguing magnetic and dipolar orders; rather, there is such an intimate link that one drives the other, suggesting a giant magnetoelectric coupling. Via first-principles approaches based on density functional theory, we review the microscopic mechanisms at the basis of multiferroicity in several compounds, ranging from transition metal oxides to organic multiferroics (MFs) to organic-inorganic hybrids (i.e. metal-organic frameworks, MOFs)