Hq. Lin et al., Exact diagonalization and quantum Monte Carlo study of the spin-1/2 XXZ model on the square lattice - art. no. 214411, PHYS REV B, 6421(21), 2001, pp. 4411
The spin-1/2 XXZ model on an infinite square lattice at zero temperature ha
s been studied and is presented here. Our methods using finite square latti
ces have been the exact diagonalization and quantum Monte Carlo methods. Th
e physical properties estimated per lattice vertex include ground-state and
first-excited-state energy, staggered magnetization, and susceptibility in
the parallel and perpendicular directions, spin stiffness, and spin-wave v
elocity. In the XXZ model range from the Ising model to the Heisenberg mode
l our estimates of physical properties compare very well with estimates by
several other methods published in several other papers. In the XXZ range b
etween the Heisenberg and XY models there is very little in the literature
to compare with our finite lattice estimates of physical properties.