Phase diagram of a two-dimensional lattice gas model of a ramp system

TL;DR

This study uses Monte Carlo simulations and fundamental measure theory to explore the phase diagram of a 2D lattice gas model with competing interactions, revealing a low-density solid phase that melts upon compression.

Contribution

It introduces a combined Monte Carlo and fundamental measure theory approach to analyze a novel 2D lattice gas model with competing interactions.

Findings

Qualitative agreement between theory and simulation of the phase diagram

Identification of a low-density solid phase that melts with compression

Model exhibits two competing interaction ranges

Abstract

Using Monte Carlo Simulation and fundamental measure theory we study the phase diagram of a two-dimensional lattice gas model with a nearest neighbor hard core exclusion and a next-to-nearest neighbors finite repulsive interaction. The model presents two competing ranges of interaction and, in common with many experimental systems, exhibits a low density solid phase, which melts back to the fluid phase upon compression. The theoretical approach is found to provide a qualitatively correct picture of the phase diagram of our model system.