Search results for "ISING MODEL"
showing 10 items of 241 documents
Anisotropic interfacial tension, contact angles, and line tensions: A graphics-processing-unit-based Monte Carlo study of the Ising model
2014
As a generic example for crystals where the crystal-fluid interface tension depends on the orientation of the interface relative to the crystal lattice axes, the nearest neighbor Ising model on the simple cubic lattice is studied over a wide temperature range, both above and below the roughening transition temperature. Using a thin film geometry $L_x \times L_y \times L_z$ with periodic boundary conditions along the z-axis and two free $L_x \times L_y$ surfaces at which opposing surface fields $\pm H_{1}$ act, under conditions of partial wetting, a single planar interface inclined under a contact angle $\theta < \pi/2$ relative to the yz-plane is stabilized. In the y-direction, a generaliza…
Spin-chain correlations in the frustrated triangular lattice material CuMnO$_2$
2020
The Ising triangular lattice remains the classic test-case for frustrated magnetism. Here we report neutron scattering measurements of short range magnetic order in CuMnO$_2$, which consists of a distorted lattice of Mn$^{3+}$ spins with single-ion anisotropy. Physical property measurements on CuMnO$_2$ are consistent with 1D correlations caused by anisotropic orbital occupation. However the diffuse magnetic neutron scattering seen in powder measurements has previously been fitted by 2D Warren-type correlations. Using neutron spectroscopy, we show that paramagnetic fluctuations persist up to $\sim$25 meV above TN= 65 K. This is comparable to the incident energy of typical diffractometers, a…
Properties of the Ising magnet confined in a corner geometry
2007
Abstract The properties of Ising square lattices with nearest neighbor ferromagnetic exchange confined in a corner geometry, are studied by means of Monte Carlo simulations. Free boundary conditions at which boundary magnetic fields ± h are applied, i.e., at the two boundary rows ending at the lower left corner a field + h acts, while at the two boundary rows ending at the upper right corner a field − h acts. For temperatures T less than the critical temperature T c of the bulk, this boundary condition leads to the formation of two domains with opposite orientation of the magnetization direction, separated by an interface which for T larger than the filling transition temperature T f ( h ) …
Nearest-neighbor Ising antiferromagnet on the fcc lattice: Evidence for multicritical behavior.
1996
The phase behavior of the Ising model with nearest-neighbor antiferromagnetic interactions on the fcc lattice in a homogeneous magnetic field is studied by means of large-scale Monte Carlo simulations. In accordance with the most recent of the previous investigations, but with significantly higher accuracy, it is found that the ``triple'' point at which the disordered phase coexists with both the AB phase as well as with the ${\mathit{A}}_{3}$B phase (corresponding to the model's lattice gas interpretation as a binary alloy ${\mathit{A}}_{\mathit{xB}1\mathrm{\ensuremath{-}}\mathit{x}}$ such as ${\mathrm{Cu}}_{\mathit{x}}$${\mathrm{Au}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$) occurs at a nonz…
Simulations of critical phenomena: from Ising models to fluids
2015
A brief retrospective is given, how simulations of critical phenomena started about 45 years ago, and how finite size scaling concepts helped to make such studies quantitative.
Single-cluster Monte Carlo study of the Ising model on two-dimensional random lattices.
1994
We use the single-cluster Monte Carlo update algorithm to simulate the Ising model on two-dimensional Poissonian random lattices with up to 80,000 sites which are linked together according to the Voronoi/Delaunay prescription. In one set of simulations we use reweighting techniques and finite-size scaling analysis to investigate the critical properties of the model in the very vicinity of the phase transition. In the other set of simulations we study the approach to criticality in the disordered phase, making use of improved estimators for measurements. From both sets of simulations we obtain clear evidence that the critical exponents agree with the exactly known exponents for regular latti…
Application of the Monte Carlo coherent-anomaly method to two-dimensional lattice-gas systems with further-neighbor interactions
1990
A Monte Carlo version of the coherent-anomaly method has been used to determine critical properties of a two-dimensional Ising ferromagnet with nearest- and next-nearest-neighbor interactions and of a series of two-dimensional lattice-gas systems of particles interacting via 6-12 Lennard-Jones potential. It has demonstrated that the method leads to quite accurate determination of critical temperature but is less successful when used to determine the values of critical exponents \ensuremath{\gamma} and \ensuremath{\nu}.
Shape of cross-over between mean-field and asymptotic critical behavior three-dimensional Ising lattice
1999
Abstract Recent numerical studies of the susceptibility of the three-dimensional Ising model with various interaction ranges have been analyzed with a cross-over model based on renormalization-group matching theory. It is shown that the model yields an accurate description of the cross-over function for the susceptibility.
Ising Spins on 3D Random Lattices
1999
We perform single-cluster Monte Carlo simulations of the Ising model on three-dimensional Poissonian random lattices of Voronoi/Delaunay type with up to 128 000 sites. For each lattice size quenched averages are computed over 96 realizations. From a finite-size scaling analysis we obtain strong evidence that the critical exponents coincide with those on regular cubic lattices.
Study of the dynamical approach to the interface localization–delocalization transition of the confined Ising model
2004
Confined magnetic Ising films in a L ? D geometry (), with short-range competing magnetic fields?(h) acting at opposite walls along the D-direction, exhibit a slightly rounded localization?delocalization transition of the interface between domains of different orientations that runs parallel to the walls. This transition is the precursor of a wetting transition that occurs in the limit of infinite film thickness () at the critical curve Tw(h). For T Tw(h)) such an interface is bounded (unbounded) to the walls, while right at Tw(h) the interface is freely fluctuating around the centre of the film. Starting from disordered configurations, corresponding to , we quench to the wetting critical t…