First-order transition features of the 3D bimodal random-field Ising model

Abstract

Two numerical strategies based on the Wang-Landau and Lee entropic sampling schemes are implemented to investigate the first-order transition features of the 3D bimodal ($\pm h$) random-field Ising model at the strong disorder regime. We consider simple cubic lattices with linear sizes in the range $L=4-32$ and simulate the system for two values of the disorder strength: $h=2$ and $h=2.25$. The nature of the transition is elucidated by applying the Lee-Kosterlitz free-energy barrier method. Our results indicate that, despite the strong first-order-like characteristics, the transition remains continuous, in disagreement with the early mean-field theory prediction of a tricritical point at high values of the random-field.

19 pages, 6 figures, slightly extended version as accepted for publication

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Cited by in corpus (2)

• Quenched bond randomness in marginal and non-marginal Ising spin models in 2D
• Wang-Landau study of the random bond square Ising model with nearest- and next-nearest-neighbor interactions