Eur. Phys. J. B (2012) 85: 240
https://doi.org/10.1140/epjb/e2012-30124-1

Colloquium

Advances in ab-initio theory of multiferroics

Materials and mechanisms: modelling and understanding

Consiglio Nazionale delle Ricerche, CNR-SPIN U.O.S. L’Aquila, Via Vetoio 10, 67100 Coppito (L’Aquila), Italy

¹ e-mail: silvia.picozzi@spin.cnr.it

Received: 10 February 2012
Received in final form: 17 May 2012
Published online: 11 July 2012

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 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 to organic-inorganic hybrids.