title: Spin liquid state in an organic Mott insulator with a triangular lattice.
abstract: 1H NMR and static susceptibility measurements have been performed in an organic Mott insulator with a nearly isotropic triangular lattice, kappa-(BEDT-TTF)2Cu2(CN)(3), which is a model system of frustrated quantum spins. The static susceptibility is described by the spin S=1/2 antiferromagnetic triangular-lattice Heisenberg model with the exchange constant J approximately 250 K. Regardless of the large magnetic interactions, the 1H NMR spectra show no indication of long-range magnetic ordering down to 32 mK, which is 4 orders of magnitude smaller than J. These results suggest that a quantum spin liquid state is realized in the close proximity of the superconducting state appearing under pressure.
authors.affiliation: Division of Chemistry, Graduate School of Science, Kyoto University, Oiwaketyo, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shimizu
authors.forename: K
authors.initials: K
authors.lastname: Miyagawa
authors.forename: K
authors.initials: K
authors.lastname: Kanoda
authors.forename: M
authors.initials: M
authors.lastname: Maesato
authors.forename: G
authors.initials: G
authors.lastname: Saito