2011/04/30 by Yuan-Ming Lu, Ying Ran, Patrick A. Lee · 7 citations
Physics and Astronomy · #Advanced Condensed Matter Physics #Computer science #Physics of Superconductivity and Magnetism #Quantum many-body systems #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.83.224413
published as Phys.Rev.B83:224413,2011 · 12 pages, 2 figures, revtex4, published version
openalex publication_date 2011/06/22 · arxiv created 2011/06/23 · arxiv updated 2015/03/18 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/06
Due to strong geometric frustration and quantum fluctuation, the S=1/2 quantum Heisenberg antiferromagnet on the kagome lattice has long been considered as an ideal platform to realize a spin liquid (SL), a phase exhibiting fractionalized excitations without any symmetry breaking. A recent numerical study (Yan et al., e-print arXiv:1011.6114) of the Heisenberg S=1/2,kagome lattice model (HKLM) shows, in contrast to earlier results, that the ground state is a singlet-gapped SL with signatures of ℤ2 topological order. Motivated by this numerical discovery, we use the projective symmetry group to classify all 20 possible Schwinger fermion mean-field states of ℤ2 SLs on the kagome lattice. Among them we found only one gapped ℤ2 SL (which we call the ℤ2[0,\ensuremathπ]\ensuremathβ state) in the neighborhood of the U(1) Dirac SL state. Since its parent state, i.e., the U(1) Dirac SL, was found [Ran et al., Phys. Rev. Lett. 98, 117205 (2007)] to be the lowest among many other candidate U(1) SLs, including the uniform resonating-valence-bond states, we propose this ℤ2[0,\ensuremathπ]\ensuremathβ state to be the numerically discovered SL ground state of the HKLM.