Abstract
We have measured and analyzed the dielectric constant of the dimer Mott insulator , which is known as a playground for a spin-liquid state. Most unexpectedly, this particular organic salt has nontrivial charge degrees of freedom, being characterized by a relaxor-like dielectric relaxation below around 60 K. This is ascribed to the charge disproportionation within the dimer due to the intersite Coulomb repulsion. A possible microscopic model is suggested and discussed.
- Received 12 March 2010
DOI:https://doi.org/10.1103/PhysRevB.82.125119
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