Abstract
We examine the perennial quantum spin liquid candidate Heisenberg antiferromagnet on the kagome lattice. Our paper is based on achieving Lanczos diagonalization of the Hamiltonian on a 48 site cluster in sectors with dimensions as large as . The results reveal intricate structures in the low-lying energy spectrum. These structures by no means unambiguously support a spin liquid ground state, but instead appear compatible with several scenarios, including fourfold topological degeneracy, inversion symmetry breaking, and a combination thereof. We discuss finite-size effects, such as the apparent absence of the eigenstate thermalization hypothesis, and note that, while considerably reduced, some are still present for the largest cluster. Finally, we observe that an XXZ model in the Ising limit reproduces remarkably well the most striking features of finite-size spectra.
- Received 5 December 2016
- Revised 7 October 2019
DOI:https://doi.org/10.1103/PhysRevB.100.155142
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