1996/07/08 by H. G. Evertz, Hans Gerd Evertz, D. P. Landau
Physics and Astronomy · #Physics of Superconductivity and Magnetism #Quantum many-body systems #Theoretical and Computational Physics #cond-mat
paper · pdf · doi:10.1103/physrevb.54.12302
published as Phys. Rev. B54 (1996) 12302 · 31 pages, LaTex, 13 figures (38 subfigures) included as eps-files, needs psfig, 260 KB
arxiv created 1996/07/08 · openalex publication_date 1996/11/01 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Using spin-dynamics techniques we have performed large-scale computer simulations of the dynamic behavior of the classical three component XY model (i.e., the anisotropic limit of an easy-plane Heisenberg ferromagnet), on square lattices of size up to 1922, for several temperatures below, at, and above TKT. The temporal evolution of spin configurations was determined numerically from coupled equations of motion for individual spins by a fourth-order predictor-corrector method, with initial spin configurations generated by a hybrid Monte Carlo algorithm. The neutron-scattering function S(q,\ensuremathω) was calculated from the resultant space-time displaced spin-spin correlation function. Pronounced spin-wave peaks were found both in the in-plane and the out-of-plane scattering function over a wide range of temperatures. The in-plane scattering function Sxx also has a large number of clear but weak additional peaks, which we interpret to come from two-spin-wave scattering. In addition, we observed a small central peak in Sxx, even at temperatures well below the phase transition. We used dynamic finite-size scaling theory to extract the dynamic critical exponent z. We find z=1.00(4) for all T\ensuremath≤TKT, in excellent agreement with theoretical predictions, although the shape of S(q,\ensuremathω) is not well described by current theory. \textcopyright 1996 The American Physical Society.