Exact Results for Itinerant Ferromagnetism in Multiorbital Systems on Square and Cubic Lattices
Exact Results for Itinerant Ferromagnetism in Multiorbital Systems on Square and Cubic Lattices
We study itinerant ferromagnetism in multiorbital Hubbard models in certain two-dimensional square and three-dimensional cubic lattices. In the strong coupling limit where doubly occupied orbitals are not allowed, we prove that the fully spin-polarized states are the unique ground states, apart from the trivial spin degeneracies, for a large region …