Static and dynamic simulation in the classical two-dimensional anisotropic Heisenberg model

By using a simulated annealing approach, Monte Carlo and molecular-dynamics techniques we have studied static and dynamic behavior of the classical two-dimensional anisotropic Heisenberg model. We have obtained numerically that the vortex 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 (Sˣˣ and Sᶻᶻ) 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. {} 1996 The American Physical Society.