Regensburg 2004 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.95: Poster
Donnerstag, 11. März 2004, 16:00–18:00, Poster D
Monte Carlo Study of the Bond-Diluted 3D Ising Model — •Wolfhard Janke3, Pierre Emmanuel Berche1, Christophe Chatelain2, and Bertrand Berche2 — 1Groupe de Physique des Matériaux, Université de Rouen, 76821 Mont Saint-Aignan Cedex, France — 2Laboratoire de Physique des Matériaux, Université Henri Poincaré, Nancy 1, BP 239, 54506 Vandœuvre les Nancy Cedex, France — 3Institut für Theoretische Physik, Universität Leipzig, Augustusplatz 10/11, 04109 Leipzig, Germany
We study by Monte Carlo simulations the influence of bond dilution on the three-dimensional Ising model. This paradigmatic model in its pure version displays a second-order phase transition with a positive specific heat critical exponent α. According to the Harris criterion the influence of disorder should hence lead to a new fixed point governed by new critical exponents. We have determined the phase diagram of the diluted model, starting from the pure model limit down to the neighbourhood of the percolation threshold. For the estimation of critical exponents, we have first performed a finite-size scaling study, where we concentrated on three different dilutions to check the stability of the disorder fixed point. Particular emphasis is placed on cross-over phenomena between the pure, disorder and percolation fixed points which lead to effective critical exponents dependent on the concentration. Furthermore, the temperature behaviour of physical quantities has been studied in order to characterize the disorder fixed point more accurately. The question of non-self-averaging at the disorder fixed point is also investigated and compared with recent results for the bond-diluted q=4 Potts model.