Berezinskii-Kosterlitz-Thouless transition in two-dimensional lattice gas models

Abstract

We have considered two classical lattice-gas models, consisting of particles that carry multicomponent magnetic momenta, and associated with a two-dimensional square lattices; each site can host one particle at most, thus implicitly allowing for hard-core repulsion; the pair interaction, restricted to nearest neighbors, is ferromagnetic and involves only two components. The case of zero chemical potential has been investigated by Grand--Canonical Monte Carlo simulations; the fluctuating occupation numbers now give rise to additional fluid-like observables in comparison with the usual saturated--lattice situation; these were investigated and their possible influence on the critical behaviour was discussed. Our results show that the present model supports a Berezinskii-Kosterlitz-Thouless phase transition with a transition temperature lower than that of the saturated lattice counterpart due to the presence of ``vacancies''; comparisons were also made with similar models studied in the literature.

6 pages, 5 figures

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Cited by in corpus (7)

• The low-temperature phase in the two-dimensional long-range diluted XY model
• First order phase transitions in classical lattice gas spin models
• Interplay of topological and structural defects in the 2D XY model
• A three-state model with competing antiferromagnetic and pairing interactions
• Interaction anisotropy and random impurities effects on the critical behaviour of ferromagnets
• The BKT Transition and its Dynamics in a Spin Fluid
• Spin vortices and vacancies: interactions and pinning on a square lattice