Phase diagram of the 3D bimodal random-field Ising model

• Published in: The European physical journal. B, Condensed matter physics Condensed matter physics, 2008, Vol.61 (1), p.111-120
• Main Authors: Fytas, N. G., Malakis, A.
• Format: Article
• Language: English
• Subjects: Complex Systems; Condensed Matter Physics; Exact sciences and technology; Fluid- and Aerodynamics; Phase transitions: general studies; Physics; Physics and Astronomy; Solid State Physics; Statistical and Nonlinear Physics; Statistical physics, thermodynamics, and nonlinear dynamical systems; Thermodynamics
• ISSN: 1434-6028; 1434-6036
• DOI: 10.1140/epjb/e2008-00039-7

. The one-parametric Wang-Landau (WL) method is implemented together with an extrapolation scheme to yield approximations of the two-dimensional (exchange-energy, field-energy) density of states (DOS) of the 3D bimodal random-field Ising model (RFIM). The present approach generalizes our earlier WL implementations, by handling the final stage of the WL process as an entropic sampling scheme, appropriate for the recording of the required two-parametric histograms. We test the accuracy of the proposed extrapolation scheme and then apply it to study the size-shift behavior of the phase diagram of the 3D bimodal RFIM. We present a finite-size converging approach and a well-behaved sequence of estimates for the critical disorder strength. Their asymptotic shift-behavior yields the critical disorder strength and the associated correlation length's exponent, in agreement with previous estimates from ground-state studies of the model.