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arXiv · 0912.4586

Uncovering the secrets of the 2d random-bond Blume-Capel model

A. Malakis·A. Nihat Berker·I. A. Hadjiagapiou·N. G. Fytas·T. Papakonstantinou
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Abstract

The effects of bond randomness on the ground-state structure, phase diagram and critical behavior of the square lattice ferromagnetic Blume-Capel (BC) model are discussed. The calculation of ground states at strong disorder and large values of the crystal field is carried out by mapping the system onto a network and we search for a minimum cut by a maximum flow method. In finite temperatures the system is studied by an efficient two-stage Wang-Landau (WL) method for several values of the crystal field, including both the first- and second-order phase transition regimes of the pure model. We attempt to explain the enhancement of ferromagnetic order and we discuss the critical behavior of the random-bond model. Our results provide evidence for a strong violation of universality along the second-order phase transition line of the random-bond version.

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A. Malakis, A. Nihat Berker, I. A. Hadjiagapiou, N. G. Fytas, T. Papakonstantinou. 2009-12-23. Uncovering the secrets of the 2d random-bond Blume-Capel model. https://doi.org/10.1016/j.physa.2009.12.064

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