Engineering multiferroism in CaMnO
arXiv:0811.2344 · doi:10.1103/PhysRevLett.102.117602
Abstract
From first-principles calculations, we investigate the structural instabilities of CaMnO. We point out that, on top of a strong antiferrodistortive instability responsible for its orthorhombic ground-state, the cubic perovskite structure of CaMnO 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 CaMnO multiferroic. We finally highlight that the FE instability of CaMnO 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.