DYNAMIC CORRELATIONS IN A CLASSICAL 2-DIMENSIONAL HEISENBERG-ANTIFERROMAGNET

A Monte Carlo molecular-dynamics calculation of the dynamic structure function S(q,) for the classical two-dimensional isotropic Heisenberg antiferromagnet is presented. For wave vectors near the antiferromagnetic Bragg point, S(q,) is well described by a product of Lorentzians representing damped spin waves. For adequately low temperatures, the dependence of the spin-wave frequency and damping on wave vector and temperature are consistent with a dynamic scaling description of Chakravarty, Halperin, and Nelson. Even for higher temperatures a scaling description is quite well satisfied, but with a modified scaling frequency. © 1990 The American Physical Society.