title: Spin-orbital exchange of strongly interacting fermions in the p band of a two-dimensional optical lattice.
abstract: Mott insulators with both spin and orbital degeneracy are pertinent to a large number of transition metal oxides. The intertwined spin and orbital fluctuations can lead to rather exotic phases such as quantum spin-orbital liquids. Here, we consider two-component (spin 1/2) fermionic atoms with strong repulsive interactions on the p band of the optical square lattice. We derive the spin-orbital exchange for quarter filling of the p band when the density fluctuations are suppressed, and show that it frustrates the development of long-range spin order. Exact diagonalization indicates a spin-disordered ground state with ferro-orbital order. The system dynamically decouples into individual Heisenberg spin chains, each realizing a Luttinger liquid accessible at higher temperatures compared to atoms confined to the s band.
authors: Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.|School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030, USA.
authors: Zhenyu
authors: Z
authors: Zhou
authors: School of Physics, Astronomy and Computational Sciences, George Mason University, Fairfax, VA 22030, USA.
authors: Erhai
authors: E
authors: Zhao
authors: Department of Physics and Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, USA.|Wilczek Quantum Center, Zhejiang University of Technology, Hangzhou 310023, China.
authors: W Vincent
authors: WV
authors: Liu