title: Critical behavior of the spin-1 Blume-Capel model on two-dimensional Voronoi-Delaunay random lattices.
abstract: The critical properties of the spin-1 Blume-Capel model in two dimensions is studied on Voronoi-Delaunay random lattices with quenched connectivity disorder. The system is treated by applying Monte Carlo simulations using the heat-bath update algorithm together with single histograms re-weighting techniques. We calculate the critical temperature as well as the critical exponents as a function of the crystal field Δ. It is found that this disordered system exhibits phase transitions of first- and second-order types that depend on the value of the crystal field. For values of Δ≤3, where the nearest-neighbor exchange interaction J has been set to unity, the disordered system presents a second-order phase transition. The results suggest that the corresponding exponent ratio belongs to the same universality class as the regular two-dimensional ferromagnetic model. There exists a tricritical point close to Δt=3.05(4) with different critical exponents. For Δt≤Δ<3.4 this model undergoes a first-order phase transition. Finally, for Δ≥3.4 the system is always in the paramagnetic phase.
authors.affiliation: Departamento de Física, Universidade Federal de Sergipe, 49100-000, São Cristovão, SE, Brazil.
authors.forename: F P
authors.initials: FP
authors.lastname: Fernandes
authors.affiliation: Departamento de Física, Universidade Federal de Sergipe, 49100-000, São Cristovão, SE, Brazil.|Departamento de Matemática, Universidade Federal de Sergipe, 49100-000 São Cristovão, SE, Brazil.
authors.forename: Douglas F
authors.initials: DF
authors.lastname: de Albuquerque
authors.affiliation: Dietrich Stauffer Computational Physics Lab, Departamento de Física, Universidade Federal do Piauí, 64049-550, Teresina, PI, Brazil.
authors.forename: F W S
authors.initials: FW
authors.lastname: Lima
authors.affiliation: Dietrich Stauffer Computational Physics Lab, Departamento de Física, Universidade Federal do Piauí, 64049-550, Teresina, PI, Brazil.|Universidade Federal da Paraíba, Centro de Ciências Exatas e da Natureza - Campus I, Departamento de Física - CCEN Cidade Universitária 58051-970 - João Pessoa, PB - Brazil.|Department of Physics and Astronomy, University of Georgia, Athens, Georgia 30602, USA.|Departamento de Física, Universidade Federal de Minas Gerais, C. P. 702, 30123-970, Belo Horizonte, MG, Brazil.
authors.forename: J A
authors.initials: JA
authors.lastname: Plascak