Electronic-structure–induced reconstruction and magnetic ordering at the LaAlO 3 |SrTiO 3 interface

Using local density approximation (LDA) calculations we predict GdFeO3-like rotation of TiO6 octahedra at the n-type interface between LaAlO3 and SrTiO3. This results in a narrowing of the Ti d bandwidth by 1/3 so that LDA+U calculations predict an antiferromagnetic, charge- and spin-ordered ground state for very modest values of U. Recent experimental evidence for magnetic interface ordering may be understood in terms of the close proximity of an antiferromagnetic insulating ground state to a ferromagnetic metallic excited state.