title: Spin-liquid phase in a spin-1/2 quantum magnet on the kagome lattice.
abstract: We study a model of hard-core bosons with short-range repulsive interactions at half filling on the kagome lattice. Using quantum Monte Carlo numerics, we find that this model shows a continuous superfluid-insulator quantum phase transition, with exponents z=1 and nu approximately 0.67(5). The insulator, I*, exhibits short-ranged density and bond correlations, topological order, and exponentially decaying spatial vison correlations, all of which point to a Z2 fractionalized phase. We estimate the vison gap in I* from the temperature dependence of the energy. Our results, together with the equivalence between hard-core bosons and S=1/2 spins, provide compelling evidence for a spin-liquid phase in an easy-axis spin-1/2 model with no special conservation laws.
authors.affiliation: Department of Physics, University of Toronto, Toronto, Ontario M5S 1A7, Canada.
authors.forename: S V
authors.initials: SV
authors.lastname: Isakov
authors.forename: Yong Baek
authors.initials: YB
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Paramekanti