Experimental evidence for a plethora of low energy spin excitations in the spin-1/2 kagome antiferromagnet ZnCu3(OH)6Cl2 may be understandable in terms of an extended Fermi surface of spinons coupled to a U(1) gauge field. We carry out variational calculations to examine the possibility that such a state may be energetically viable. A Gutzwiller-projected wavefunction reproduces the dimerization of a kagome strip found previously by DMRG. Application to the full kagome lattice shows that the inclusion of a small ferromagnetic next-nearest-neighbor interaction favors a ground state with a spinon Fermi surface.
@article{arxiv.0801.2138,
title = {Weak Ferromagnetic Exchange and Anomalous Specific Heat in ZnCu3(OH)6Cl2},
author = {Ookie Ma and J. B. Marston},
journal= {arXiv preprint arXiv:0801.2138},
year = {2009}
}
Comments
4 pages, 3 figures, some clarifications to the text