title: First-order phase transitions in repulsive rigid k-mers on two-dimensional lattices.
abstract: In a previous paper [F. Romá, A. J. Ramirez-Pastor, and J. L. Riccardo, Phys. Rev. B 72, 035444 (2005)], the critical behavior of repulsive rigid rods of length k (k-mers) on a square lattice at half coverage has been studied by using Monte Carlo (MC) simulations. The obtained results indicated that (1) the phase transition occurring in the system is a second-order phase transition for all adsorbate sizes k; and (2) the universality class of the transition changes from 2D Ising-type for monomers (k = 1) to an unknown universality class for k ≥ 2. In the present work, we revisit our previous results together with further numerical evidences, resulting from new extensive MC simulations based on an efficient exchange algorithm and using high-performance computational capabilities. In contrast to our previous conclusions (1) and (2), the new numerical calculations clearly support the occurrence of a first-order phase transition for k ≥ 2. In addition, a similar scenario was found for k-mers adsorbed on the triangular lattice at coverage k/(2k+1).
authors.affiliation: Departamento de Física, Instituto de Física Aplicada (INFAP), Universidad Nacional de San Luis,CONICET, Chacabuco 917, D5700BWS, San Luis, Argentina. pmp@unsl.edu.ar
authors.forename: P M
authors.initials: PM
authors.lastname: Pasinetti
authors.forename: F
authors.initials: F
authors.lastname: Romá
authors.forename: A J
authors.initials: AJ
authors.lastname: Ramirez-Pastor
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D008956:Models, Chemical; D009010:Monte Carlo Method; D044367:Phase Transition; D013816:Thermodynamics