Transfer-matrix study of a hard-square lattice gas with two kinds of particles and density anomaly

Abstract

Using transfer matrix and finite-size scaling methods, we study the thermodynamic behavior of a lattice gas with two kinds of particles on the square lattice. Only excluded volume interactions are considered, so that the model is athermal. Large particles exclude the site they occupy and its four first neighbors, while small particles exclude only their site. Two thermodynamic phases are found: a disordered phase where large particles occupy both sublattices with the same probability and an ordered phase where one of the two sublattices is preferentially occupied by them. The transition between these phases is continuous at small concentrations of the small particles and discontinuous at larger concentrations, both transitions are separated by a tricritical point. Estimates of the central charge suggest that the critical line is in the Ising universality class, while the tricritical point has tricritical Ising (Blume-Emery-Griffiths) exponents. The isobaric curves of the total density as functions of the fugacity of small or large particles display a minimum in the disordered phase.

9 pages, 7 figures and 4 tables

References in corpus (3)

• Monte Carlo simulations of 2d hard core lattice gases
• A Monte Carlo study of the triangular lattice gas with the first- and the second-neighbor exclusions
• Polydispersed rods on the square lattice

Cited by in corpus (8)

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• Thermodynamic behavior of binary mixtures of hard spheres: Semianalytical solutions on a Husimi lattice built with cubes
• Fluid-fluid demixing and density anomaly in a ternary mixture of hard spheres
• Phase diagram and critical properties of a two-dimensional associating lattice gas
• Rejection-free cluster Wang-Landau algorithm for hard-core lattice gases