The effect of anisotropy on the ground-state magnetic ordering of the spin-1 quantum J1XXZ–J2XXZ model on the square lattice

• Published in: Journal of physics. Condensed matter 2008-10, Vol.20 (41), p.415213-415213 (11)
• Main Authors: Bishop, R F, Li, P H Y, Darradi, R, Richter, J, Campbell, C E
• Format: Article
• Language: English
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/20/41/415213

We study the zero-temperature phase diagram of the J1XXZ-J2XXZ Heisenberg model for spin-1 particles on an infinite square lattice interacting via nearest-neighbour () and next-nearest-neighbour (J2 > 0) bonds. The two bonds have the same XXZ-type anisotropy in spin space. The effects on the quasiclassical Neel-ordered and collinear stripe-ordered states of varying the anisotropy parameter Delta are investigated using the coupled cluster method carried out up to high orders. By contrast with the case for spin- particles studied previously, no intermediate disordered phase between the Neel and collinear stripe phases, for any value of the frustration J2/J1, for either the z-aligned (Delta > 1) or xy-planar-aligned (0 < =Delta < 1) states, is predicted here. The quantum phase transition is determined as first order for all values of J2/J1 and Delta. The position of the phase boundary J2c(Delta) is determined accurately. It is observed to deviate most from its classical position (for all values of Delta > 0) at the Heisenberg isotropic point (Delta = 1), where J2c(1) = 0.55 +/- 0.01. By contrast, at the XY isotropic point (Delta = 0), we find J2c(0) = 0.50 +/- 0.01. In the Ising limit (), as expected.