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Article Dans Une Revue Physical Review B: Condensed Matter and Materials Physics (1998-2015) Année : 2014

Vanishing spin gap in a competing spin-liquid phase in the kagome Heisenberg antiferromagnet

Résumé

We provide strong numerical evidence, using improved variational wave functions, for a ground state with vanishing spin gap in the spin-1/2 quantum Heisenberg model on the kagome lattice. Starting from the algebraic U(1) Dirac spin liquid state proposed by Y. Ran et al. [Phys. Rev. Lett. 98, 117205 (2007)] and iteratively applying a few Lanczos steps, we compute the lowest S=2 excitation constructed by exciting spinons close to the Dirac nodes. Our results are compatible with a vanishing spin gap in the thermodynamic limit and in consonance with a power-law decay of long distance spin-spin correlations in real space. The competition with a gapped (topological) spin liquid is discussed.

Dates et versions

hal-00907328 , version 1 (21-11-2013)

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Yasir Iqbal, Didier Poilblanc, Federico Becca. Vanishing spin gap in a competing spin-liquid phase in the kagome Heisenberg antiferromagnet. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2014, 89 (2), pp.020407. ⟨10.1103/PhysRevB.89.020407⟩. ⟨hal-00907328⟩
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