title: Monte Carlo study of anisotropic scaling generated by disorder.
abstract: We analyze the critical properties of the three-dimensional Ising model with linear parallel extended defects. Such a form of disorder produces two distinct correlation lengths, a parallel correlation length ξ(∥) in the direction along defects and a perpendicular correlation length ξ(⊥) in the direction perpendicular to the lines. Both ξ(∥) and ξ(⊥) diverge algebraically in the vicinity of the critical point, but the corresponding critical exponents ν(∥) and ν(⊥) take different values. This property is specific for anisotropic scaling and the ratio ν(∥)/ν(⊥) defines the anisotropy exponent θ. Until now, estimates of quantitative characteristics of the critical behavior for such systems have been obtained only within the renormalization group approach. We report a study of the anisotropic scaling in this system via Monte Carlo simulation of the three-dimensional system with Ising spins and nonmagnetic impurities arranged into randomly distributed parallel lines. Several independent estimates for the anisotropy exponent θ of the system are obtained, as well as an estimate of the susceptibility exponent γ. Our results corroborate the renormalization group predictions obtained earlier.
authors.affiliation: Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, D-70569 Stuttgart, Germany and IV. Institut für Theoretische Physik, Universität Stuttgart, Pfaffenwaldring 57, D-70569 Stuttgart, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Vasilyev
authors.affiliation: Statistical Physics Group, Institut Jean Lamour, UMR CNRS 7198 and Université de Lorraine, B.P. 70239, F-54506 Vandœuvre lès Nancy Cedex, France.
authors.forename: B
authors.initials: B
authors.lastname: Berche
authors.affiliation: Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, UA-79011 Lviv, Ukraine.
authors.forename: M
authors.initials: M
authors.lastname: Dudka
authors.affiliation: Institute for Condensed Matter Physics, National Academy of Sciences of Ukraine, UA-79011 Lviv, Ukraine.
authors.forename: Yu
authors.initials: Y
authors.lastname: Holovatch