INFLUENCE OF QUANTUM FLUCTUATIONS ON THE NEEL TEMPERATURE OF A DILUTE2-DIMENSIONAL ANISOTROPIC ANTIFERROMAGNET

A quantum Monte Carlo procedure is used to calculate the energy, subla ttice magnetization, Neel temperature, and the slopes of the S=[l/T-N( x=0)]dT(N)(x)/dx curves as functions of the hole concentration and the exchange anisotropy Delta=1-J(x,y)/J(z) in the Heisenberg model with anisotropic negative interactions between nearest neighbors in a squar e lattice with dilution among the lattice sites. The slope diverges in the limit Delta-->0:S similar to ln(6.5/Delta). (C) 1997 American Ins titute of Physics.