A. Schmitt et al., THE SPIN-1 LAI-SUTHERLAND MODEL WITH EXTERNAL AND INTERNAL FIELDS .1.THE PHASE-DIAGRAM, Journal of physics. A, mathematical and general, 29(14), 1996, pp. 3951-3962
The one-dimensional S = 1 quantum spin chain with a linear and bilinea
r nearest-neighbour interaction of equal strength is integrable by the
nested Bethe ansatz. In this paper the model is studied in the presen
ce of an external magnetic held and an internal crystal field. By solv
ing the Bethe ansatz equations for chains up to length N = 360 we cons
truct the complete phase diagram of the system. We discuss how the mag
netization curves depend on the internal field. In the SU(3) phase, wh
ere all three densities of atoms with Sc-component -1, 0, +1 are non-v
anishing, lines of constant density can be approximately parametrized
by modified hypocycloides.