• DOI:10.1103/PhysRevB.89.020407
• Corpus ID: 119281480

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

@article{Iqbal2014VanishingSG,
  title={Vanishing spin gap in a competing spin-liquid phase in the kagome Heisenberg antiferromagnet},
  author={Yasir Iqbal and Didier Poilblanc and Federico Becca},
  journal={Physical Review B},
  year={2014},
  volume={89},
  pages={020407-020407}
}

• Y. Iqbal, D. Poilblanc, F. Becca
• Published 20 November 2013
• Physics
• Physical Review B

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 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.