Mean spin per site in the linearised spin-wave theory of a dilute two dimensional antiferromagnet

The authors compute the mean spin per site (S^z) using the linearised randomly dilute two-dimensional antiferromagnetic Heisenberg model developed by Thorpe and Alben. The result shows that (S- mod (S^z) mod )/S is 14-16% near the percolation concentration. Mean spins on small finite clusters in this model are in very poor agreement with exact results of (S ^z)=0 for H_A=0. The mean spin on the largest cluster is reasonably self-consistent but spatial inhomogeneities in (S_i ^z) are not treated self-consistently in the model.