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 ground state of the antiferromagnetic Ising model on a triangular lattice. At zero temperature its modulation on the sublattices gives rise to two 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 zero temperature pair correlation function. The size dependence of our simulation data is investigated through a novel finite-size scaling analysis where t=e−2/T is used as the temperature parameter.