https://doi.org/10.1007/s100510050004
Ground state phase diagram of a spin-2 antiferromagnet on the square lattice*
Institut für Theoretische Physik, Zülpicher Strasse 77, 50937 Köln, Germany
Corresponding author: a hn@thp.uni-koeln.de
Received:
8
April
1999
Published online: 15 January 2000
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.
PACS: 75.10.Jm – Quantized spin models / 05.50.+q – Lattice theory and statistics (Ising, Potts, etc.)
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2000
