Monte Carlo and spin dynamics study of the anisotropic Heisenberg model in two dimensions

Abstract
By using Monte Carlo and molecular dynamics we study the static as well as the dynamical behavior of the classical two dimensional anisotropic Heisenberg model. Our results show that the vortices developed in such a model exhibit two different behaviors depending if the value of the anisotropy λ lies below or above a critical value λc. The in-plane and out-of-plane correlation functions were obtained numerically for λ<λc and λ>λc. We found that the out-of-plane dynamical correlation function exhibits a central peak for λ>λc but not for λ<λc at temperatures above TKT.