Abstract
The organic triangular-lattice 1/2-spin system EtMeSb[Pd(dmit)] does not undergo classical antiferromagnetic ordering and is a strong candidate for a quantum spin liquid. It is currently an open issue whether or not the ground state of this system has a broken-symmetry and/or topological structure, and what kind of excitations the ground state has. We have performed NMR measurements on the inner carbons of the Pd(dmit) molecule in order to get reliable information on this issue. By comparing the inner-carbon NMR data with the previously obtained outer-carbon data, we have reached a robust conclusion that these NMR data are not affected by cation molecular motion and definitely reflect the spin state of this system. The temperature dependencies of the spin-lattice relaxation rates suggest that the spin state undergoes an abrupt change at around 1 K, and, thus, the ground state is likely to have a broken-symmetry and/or topological structure. The rates also strongly indicate that the imaginary part of the -integrated dynamic susceptibility () disappears as .
- Received 4 August 2011
DOI:https://doi.org/10.1103/PhysRevB.84.094405
©2011 American Physical Society