Ground state phase diagram of a spin-2 antiferromagnet on the square lattice |
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Authors: | H. Niggemann A. Klümper J. Zittartz |
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Affiliation: | Institut für Theoretische Physik, Zülpicher Strasse 77, 50937 K?ln, Germany, DE
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Abstract: | We use the vertex state model approach to construct optimum ground states for a large class of quantum spin-2 antiferromagnets on the square lattice. Optimum ground states are exact ground states of the model which minimize all local interaction operators. The ground state contains two continuous parameters and exhibits a second order phase transition from a disordered phase with exponentially decaying correlation functions to a Néel ordered phase. The behaviour is very similar to that of the corresponding ground state of a quantum spin-3/2 model on the hexagonal lattice, which has been investigated in an earlier paper. Received 8 April 1999 |
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Keywords: | PACS. 75.10.Jm Quantized spin models - 05.50.+q Lattice theory and statistics (Ising Potts etc.) |
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