MONTE-CARLO STUDY OF CORRELATIONS NEAR THE GROUND-STATE OF THE TRIANGULAR ANTIFERROMAGNETIC ISING-MODEL

We study the spin-spin correlation function in or near the T = 0 groun d slate of the antiferromagnetic Ising model on a triangular lattice. At zero temperature its modulation on the sublattices gives rise to tw o Bragg peaks in the structure factor, and a known expression for the algebraic decay of correlations enables us to examine the form of the diffusive scattering. We do so by means of a comparison between exact results and data calculated using standard Monte Carlo techniques. At non-zero temperatures the finite correlation length alters this form, and we account for the change by proposing a generalisation of the zer o temperature pair correlation function. The size dependence of our si mulation data is investigated through a novel finite-size scaling anal ysis where t = e(-2/T) is used as the temperature parameter.