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arXiv · 1006.5649

Effective spin model for the spin-liquid phase of the Hubbard model on the triangular lattice

H-Y. Yang·A. Laeuchli·F. Mila·K. P. Schmidt
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Abstract

We show that the spin liquid phase of the half-filled Hubbard model on the triangular lattice can be described by a pure spin model. This is based on a high-order strong coupling expansion (up to order 12) using perturbative continuous unitary transformations. The resulting spin model is consistent with a transition from three-sublattice long-range magnetic order to an insulating spin liquid phase, and with a jump of the double occupancy at the transition. Exact diagonalizations of both models show that the effective spin model is quantitatively accurate well into the spin liquid phase, and a comparison with the Gutzwiller projected Fermi sea suggests a gapless spectrum and a spinon Fermi surface.

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H-Y. Yang, A. Laeuchli, F. Mila, K. P. Schmidt. 2011-01-14. Effective spin model for the spin-liquid phase of the Hubbard model on the triangular lattice. https://doi.org/10.1103/physrevlett.105.267204

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