Numerical investigation of the role of topological defects in the three-dimensional Heisenberg transition

Lau, Man-hot ; Dasgupta, Chandan (1989) Numerical investigation of the role of topological defects in the three-dimensional Heisenberg transition Physical Review B, 39 (10). pp. 7212-7222. ISSN 0163-1829

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Official URL: http://prb.aps.org/abstract/PRB/v39/i10/p7212_1

Related URL: http://dx.doi.org/10.1103/PhysRevB.39.7212

Abstract

The role of topological point defects (hedgehogs) in the phase transition of the classical Heisenberg model in three dimensions is investigated by using Monte Carlo simulations. Simulations of the behavior of the defects near the phase transition show that the number density of defects increases sharply and defect pairs with separations comparable to the sample size begin to appear as the temperature is increased through the transition temperature. In simulations in a restricted ensemble in which spin configurations containing defects are not allowed, the system appears to remain ordered at all temperatures. Simulations in which the spin-spin interaction is set equal to zero and the number density of defects is controlled by varying a "chemical potential" term indicate that the system is ordered if the number density of defect pairs is sufficiently small. These results show that topological defects play a crucial role in the three-dimensional Heisenberg transition in the sense that configurations containing defect pairs are necessary for the transition from the ferromagnetic to the paramagnetic phase to occur.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:22826
Deposited On:25 Nov 2010 14:00
Last Modified:07 Feb 2011 05:33

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