Using a combination of density functional theory and dynamical mean field theory we show that electric polarization and magnetism are strongly intertwined in (TMTTF)2-X (X=PF6, AsF6, and SbF6) organic crystals and they originate from short-range Coulomb interactions. Electronic correlations induce a charge-ordered state which, combined with the molecular dimerization, gives rise to a finite electronic polarization and to a ferroelectric state. We predict that the value of the electronic polarization is enhanced by the onset of antiferromagnetism showing a sizable magnetoelectric leading to a multiferroic behavior of (TMTTF)2-X compounds.
@article{arxiv.1405.1528,
title = {Correlation-driven electronic multiferroicity in (TMTTF)$_2$-$X$ organic crystals},
author = {G. Giovannetti and R. Nourafkan and G. Kotliar and M. Capone},
journal= {arXiv preprint arXiv:1405.1528},
year = {2015}
}