Exotic magnetic orders for high spin ultracold fermions

Abstract

We study Hubbard models for ultracold bosonic or fermionic atoms loaded into an optical lattice. The atoms carry a high spin $F>1/2$, and interact on site via strong repulsive Van der Waals forces. Making convenient rearrangements of the interaction terms, and exploiting their symmetry properties, we derive low energy effective models with nearest-neighbor interactions, and their properties. We apply our method to $F=3/2$, and 5/2 fermions on two-dimensional square lattice at quarter, and 1/6 fillings, respectively, and investigate mean-field equations for repulsive couplings. We find for $F=3/2$ fermions that the plaquette state appearing in the highly symmetric SU(4) case does not require fine tuning, and is stable in an extended region of the phase diagram. This phase competes with an SU(2) flux state, that is always suppressed for repulsive interactions in absence of external magnetic field. The SU(2) flux state has, however, lower energy than the plaquette phase, and stabilizes in the presence of weak applied magnetic field. For $F=5/2$ fermions a similar SU(2) plaquette phase is found to be the ground state without external magnetic field.

final version, 6 pages, 4 figures, epl format

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Cited by in corpus (29)

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• SU(N) magnetism in chains of ultracold alkaline-earth-metal atoms: Mott transitions and quantum correlations
• Competing orders in the 2D half-filled SU(2N) Hubbard model through the pinning field quantum Monte-Carlo simulations
• Gauge fields emerging from time reversal symmetry breaking for spin-5/2 fermions in a honeycomb lattice
• Pomeranchuk cooling of the SU($2N$) ultra-cold fermions in optical lattices
• Quantum Monte Carlo simulation of thermodynamic properties of SU(2N) ultracold fermions in optical lattices
• Quantum magnetism of ultra-cold fermion systems with the symplectic symmetry
• Critical entropies and magnetic-phase-diagram analysis of ultracold three-component fermionic mixtures in optical lattices
• Variational Monte-Carlo investigation of SU($N$) Heisenberg chains
• Structure of Spin Correlations in High Temperature SU($N$) Quantum Magnets
• Tetramerization in a SU(4)-Heisenberg model on the honeycomb lattice
• Breaking of SU(4) symmetry and interplay between strongly correlated phases in the Hubbard model
• Mott insulators of ultracold fermionic alkaline earth atoms in three dimensions
• SU(4)-symmetric Hubbard model at quarter filling: Insights from the dynamical mean-field approach
• Spin liquid phases of alkaline-earth-metal atoms at finite temperature
• Competing valence bond and symmetry breaking Mott states of spin-3/2 fermions on a honeycomb lattice
• Magnetic field induced band insulator to Mott insulator transformations in 4-component alkali fermions at half-filling
• Two-orbital physics of high spin fermionic alkaline earth atoms confined in a one-dimensional chain
• Emergence of Quintet Superfluidity in the Chain of Partially Polarized Spin-3/2 Ultracold Atom
• The Symplectic Fermi Liquid and its realization in cold atomic systems
• Spin liquid phases of Mott insulating ultracold bosons
• Quantum dimer models emerging from large-spin ultracold atoms
• Competing Valence Bond States of Spin-3/2 Fermions on a Strongly Coupled Ladder
• Order by disorder in a four flavor Mott-insulator on the fcc lattice
• Nonrelativistic Banks-Casher relation and random matrix theory for multi-component fermionic superfluids
• Ground-state phase diagram of the SU($4$) Heisenberg model on a plaquette lattice