Orbital Ordering in Ferromagnetic Lu₂V₂O₇

Abstract

We have observed the orbital ordering in the ferromagnetic Mott-insulator Lu₂V₂O₇ by the polarized neutron diffraction technique. The orbital ordering pattern determined from the observed magnetic form factors can be explained in terms of a linear combination of wave functions |yz⟩, |zx⟩ and |xy⟩; | 0 ⟩& = \\sqrt\\frac13| xy ⟩+ \\sqrt\\frac13| yz ⟩+ \\sqrt\\frac13| zx ⟩
& ∝| (x+y+z)^2-r^2 ⟩, where each orbital is extended toward the center-of-mass of the V tetrahedron. We discuss the stability of the ferromagnetic Lu₂V₂O₇, using a Hubbard Hamiltonian with these three orbitals.