Magnetic transition and spin-polarized two-dimensional electron gas controlled by polarization switching in strained CaMnO_3/BaTiO_3 slabs

Ab initio calculations show the presence of a strong magnetoelectric interfacial coupling in CaMnO_3 ultra-thin film grown on a strained BaTiO_3 ferroelectric film. This heterostructure presents a polarization driven magnetic transition from a G-type to an A-type antiferromagnetic structure. Together with this magnetic transition we find a metallic behaviour at the interface between these two insulators, where the charge character of the carriers can be tuned from electrons to holes by switching the electric polarization direction of the FE film. Besides, the electron gas is spin-polarized while the hole-gas is not.