High mobility half-metallicity in the (LaMnO₃) ₂/(SrTiO₃)₈ superlattice

First principles calculations have been performed to investigate the LaMnO₃/SrTiO₃ superlattice. Structural relaxation within the generalized gradient approximation results in no significant tiltings or rotations of oxygen octahedra, but in distinct distortions in the SrTiO ₃ region. Taking into account the onsite Coulomb interaction, we find that the Mn spins order ferromagnetically, in contrast to the antiferromagnetic state of bulk LaMnO₃. Most importantly, the interface strain combined with charge transfer across the interface induces half-metallicity within the MnO₂ layers. The superlattice is particulary interesting for spintronics applications because the half-metallic states are characterized by an extraordinary high mobility.