Monte Carlo study of the magnetic critical properties of the two-dimensional Ising fluid

TL;DR

This study uses Monte Carlo simulations to analyze the magnetic phase transition in a two-dimensional Ising fluid, estimating critical exponents and comparing them to the lattice Ising model.

Contribution

It provides the first detailed Monte Carlo analysis of the critical properties of a 2D Ising fluid, highlighting differences in the correlation length exponent.

Findings

Critical exponents $eta/ u$ and $\gamma/ u$ match 2D lattice Ising model.

The correlation length exponent $ u$ differs significantly from the lattice Ising value.

Transition point and critical behavior are characterized for the 2D Ising fluid.

Abstract

A two-dimensional fluid of hard spheres each having a spin $\pm 1$ and interacting via short-range Ising-like interaction is studied near the second order phase transition from the paramagnetic gas to the ferromagnetic gas phase. Monte Carlo simulation technique and the multiple histogram data analysis were used. By measuring the finite-size behaviour of several different thermodynamic quantities,we were able to locate the transition and estimate values of various static critical exponents. The values of exponents $\beta/\nu$ and $\gamma/\nu$ are close to the ones for the two-dimensional lattice Ising model. However, our result for the exponent $\nu =1.35$ is very different from the one for the Ising universality class.