Abstract
NMR and static susceptibility measurements have been performed in an organic Mott insulator with a nearly isotropic triangular lattice, , which is a model system of frustrated quantum spins. The static susceptibility is described by the spin antiferromagnetic triangular-lattice Heisenberg model with the exchange constant . Regardless of the large magnetic interactions, the NMR spectra show no indication of long-range magnetic ordering down to 32 mK, which is 4 orders of magnitude smaller than . These results suggest that a quantum spin liquid state is realized in the close proximity of the superconducting state appearing under pressure.
- Received 15 July 2002
DOI:https://doi.org/10.1103/PhysRevLett.91.107001
©2003 American Physical Society