Abstract
We study the energetics of Gutzwiller projected BCS states of various symmetries for the triangular lattice antiferromagnet with a four-particle ring exchange using variational Monte Carlo methods. In a range of parameters the energetically favored state is found to be a projected paired state which breaks lattice rotational symmetry. We show that the properties of this nematic or orientationally ordered paired spin-liquid state as a function of temperature and pressure can account for many of the experiments on organic materials. We also study the ring-exchange model with ferromagnetic Heisenberg exchange and find that among the studied ansätze, a projected -wave state is the most favorable.
- Received 7 March 2010
DOI:https://doi.org/10.1103/PhysRevB.81.245121
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