From first-principles calculations, we investigate the structural instabilities of CaMnO3. We point out that, on top of a strong antiferrodistortive instability responsible for its orthorhombic ground-state, the cubic perovskite structure of CaMnO3 also exhibit a weak ferroelectric instability. Although ferroelectricity is suppressed by antiferrodistortive oxygen motions, we show that it can be favored using strain or chemical engineering in order to make CaMnO3 multiferroic. We finally highlight that the FE instability of CaMnO3 is Mn-dominated. This illustrates that, contrary to the common believe, ferroelectricity and magnetism are not necessarily exclusive but can be driven by the same cation.
@article{arxiv.0811.2344,
title = {Engineering multiferroism in CaMnO$_3$},
author = {Satadeep Bhattacharjee and Eric Bousquet and Philippe Ghosez},
journal= {arXiv preprint arXiv:0811.2344},
year = {2009}
}