Spin, Orbital, and Charge Order at the Interface between Correlated Oxides

The collective behavior of correlated electrons in the VO2 interface layer of the LaVO3/SrTiO3 heterostructure is studied within a quarter-filled t(2g)-orbital Hubbard model on a square lattice. We argue that the ground state is ferromagnetic, driven by the double-exchange mechanism, and is orbitally and charge ordered due to a confined geometry and electron correlations. The orbital and charge density waves open gaps on the entire Fermi surfaces of all orbitals. The theory explains the observed insulating behavior of the p-type interface between LaVO3 and SrTiO3.