title: Spin dynamics of the spin-1/2 kagome lattice antiferromagnet ZnCu3(OH)6Cl2.
abstract: We have performed thermodynamic and neutron scattering measurements on the S=1/2 kagomé lattice antiferromagnet ZnCu3(OH)6Cl2. The susceptibility indicates a Curie-Weiss temperature of theta CW approximately = -300 K; however, no magnetic order is observed down to 50 mK. Inelastic neutron scattering reveals a spectrum of low energy spin excitations with no observable gap down to 0.1 meV. The specific heat at low-T follows a power law temperature dependence. These results suggest that an unusual spin liquid state with essentially gapless excitations is realized in this kagomé lattice system.
authors.affiliation: Department of Physics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: J S
authors.initials: JS
authors.lastname: Helton
authors.forename: K
authors.initials: K
authors.lastname: Matan
authors.forename: M P
authors.initials: MP
authors.lastname: Shores
authors.forename: E A
authors.initials: EA
authors.lastname: Nytko
authors.forename: B M
authors.initials: BM
authors.lastname: Bartlett
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: Y
authors.initials: Y
authors.lastname: Takano
authors.forename: A
authors.initials: A
authors.lastname: Suslov
authors.forename: Y
authors.initials: Y
authors.lastname: Qiu
authors.forename: J-H
authors.initials: JH
authors.lastname: Chung
authors.forename: D G
authors.initials: DG
authors.lastname: Nocera
authors.forename: Y S
authors.initials: YS
authors.lastname: Lee