The quantum J1-J'1-J2 spin-1 Heisenberg model: Influence of the interchain coupling on the ground-state magnetic ordering in 2DR. F. Bishop1, 2, P. H. Y. Li1, 2, R. Darradi3 and J. Richter3
1 School of Physics & Astronomy, Schuster Building, The University of Manchester - Manchester, M13 9PL, UK, EU
2 School of Physics & Astronomy, University of Minnesota - 116 Church St. SE, Minneapolis, MN 55455, USA
3 Institut für Theoretische Physik, Universität Magdeburg - 39016 Magdeburg, Germany, EU
received 21 April 2008; accepted in final form 25 June 2008; published August 2008
published online 30 July 2008
We study the phase diagram of the isotropic J1- J'1-J2 Heisenberg model for spin-1 particles on an anisotropic square lattice, using the coupled-cluster method. We find no evidence for an intermediate phase between the Néel and stripe states, as compared with all previous results for the corresponding spin-1/2 case. However, we find a quantum tricritical point at J'1/J1 0.66 0.03, J2/J1 0.35 0.02, where a line of second-order phase transitions between the quasi-classical Néel and stripe-ordered phases (for J'1/J1 0.66) meets a line of first-order phase transitions between the same two states (for J'1/J1 0.66).
75.10.Jm - Quantized spin models.
75.30.Gw - Magnetic anisotropy.
75.50.Ee - Antiferromagnetics.
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