Phase diagram of a square-well model in two dimensions

Abstract

The following article appeared in Journal of Chemical Physics 140.6 (2014): 064503 and may be found at http://scitation.aip.org/content/aip/journal/jcp/140/6/10.1063/1.4863993The phase behavior of a two-dimensional square-well model of width 1.5σ, with emphasis on the low-temperature and/or high-density region, is studied using Monte Carlo simulation in the canonical and isothermal-isobaric ensembles, and discontinuous molecular-dynamics simulation in the canonical ensemble. Several properties, such as equations of state, Binder cumulant, order parameters, and correlation functions, were computed. Numerical evidence for vapor, liquid, hexatic, and triangular solid is given, and, in addition, a non-compact solid with square-lattice symmetry is obtained. The global phase diagram is traced out in detail (or sketched approximately whenever only inaccurate information could be obtained). The solid region of the phase diagram is explained using a simple mean-field modelThe authors acknowledge the following financial support: “Investigación realizada gracias al Programa UNAMDGAPA- PAPIIT IN104111-2 Transiciones de fases y agregados moleculares en 2 dimensiones;” CONACYT grant Efecto de la quiralidad, polaridad y anisotropía en el auto-ensamblaje molecular en dos dimensiones. J.C.A.-P. is grateful for a scholarship from CONACYT. We acknowledge financial support from programme MODELICOCM/ S2009ESP-1691 (Comunidad Autónoma de Madrid, Spain), and FIS2010-22047-C01 and FIS2010-22047-C04 (MINECO, Spain