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arXiv · 0903.1630

Phase diagram of the Heisenberg antiferromagnet with four-spin interactions

L. Isaev·G. Ortiz·J. Dukelsky
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Abstract

We study the quantum phase diagram of the Heisenberg planar antiferromagnet with a subset of four-spin ring exchange interactions, using the recently proposed heirarchical mean-field approach. By identifying relevant degrees of freedom, we are able to use a single variational anzatz to map the entire phase diagram of the model and uncover the nature of its various phases. It is shown that there exists a transition between a N\'eel state and a quantum paramagnetic phase, characterized by broken translational invariance. The non-magnetic phase preserves the lattice rotational symmetry, and has a correlated plaquette nature. Our results also suggest that this phase transition can be properly described within the Landau paradigm.

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L. Isaev, G. Ortiz, J. Dukelsky. 2009-03-09. Phase diagram of the Heisenberg antiferromagnet with four-spin interactions. https://doi.org/10.1088/0953-8984/22/1/016006

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