Monte Carlo analysis of critical properties of the twodimensional randomly sitediluted Ising model via Wang Landau algorithm
Abstract
The influence of random site dilution on the critical properties of the twodimensional Ising model on a square lattice was explored by Monte Carlo simulations with the WangLandau sampling. The lattice linear size was L=20120 and the concentration of diluted sites q=0.1,0.2,0.3. Its pure version displays a secondorder phase transition with a vanishing specific heat critical exponent α, thus, the Harris criterion is inconclusive, in that disorder is a relevant or irrelevant perturbation for the critical behaviour of the pure system. The main effort was focused on the specific heat and magnetic susceptibility. We have also looked at the probability distribution of susceptibility, pseudocritical temperatures and specific heat for assessing selfaveraging. The study was carried out in appropriate restricted but dominant energy subspaces. By applying the finitesize scaling analysis, the correlation length exponent ν was found to be greater than one, whereas the ratio of the critical exponents ( α/ν) is negative and ( γ/ν) retains its pure Ising model value supporting weak universality.
 Publication:

Physica A Statistical Mechanics and its Applications
 Pub Date:
 April 2008
 DOI:
 10.1016/j.physa.2007.12.007
 arXiv:
 arXiv:0807.0075
 Bibcode:
 2008PhyA..387.2256H
 Keywords:

 Condensed Matter  Statistical Mechanics;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 18 pages, 5 figure