INVESTIGADORES
DE VIRGILIIS Andres
artículos
Título:
Interfaces in the confined Ising system with competing surface fields
Autor/es:
A. DE VIRGILIIS; E. V. ALBANO; M. MUELLER; K. BINDER
Revista:
PHYSICA A - STATISTICAL AND THEORETICAL PHYSICS
Editorial:
Elsevier
Referencias:
Año: 2005 vol. 352 p. 477 - 497
ISSN:
0378-4371
Resumen:
When a magnetic Ising film is confined in a L×M geometry (LM) short-range competing magnetic fields (h1) are applied at opposite walls along the M-direction,
a (weakly rounded) localizationdelocalization transition of the
interface between domains of different orientation that runs parallel
to walls can be observed. This transition is the precursor of a wetting
phase transition that occurs in the limit of infinite film thickness (L→∞) at the critical curve Tw(h1). For such an interface is bound to (unbound from) the walls, while right at Tw(h1)
the interface is freely fluctuating around the center of the film. We
present extensive Monte Carlo simulations of Ising stripes in the L×M
geometry, in order to describe both the localizationdelocalization
transition and the properties of the delocalized interface. To this
aim, we take advantage of several available theoretical results. We
make use of a suitable algorithm to define the local position of the
interface along the film, such that its probability distribution can be
used to account for the transition itself and the fluctuations in the
local position of the interface (capillary waves). After describing the
interface localizationdelocalization transition, we pay attention to
the properties of the delocalized interface with an emphasis on the
effects of confinement. We analyze several quantities of interest in
terms of the film thickness L. The width of the capillary waves (s) can be related to the width of the magnetization profiles (w) by means of a simple approximation. From this relation we estimate a value for the intrinsic width (w0) of the interface which agrees with the theoretical one. Also the correlation length ξ along the film is considered, and the behavior ξL2 compares very well to available exact results. Additionally, the interfacial stiffness βΓ obtained from the Fourier spectrum of the capillary waves reproduces the asymptotic theoretical value.