Phase diagram of the system with the repulsive shoulder potential in two dimensions: density functional approach

TL;DR

This study uses density functional theory to map the phase diagram of a two-dimensional particle system with a repulsive shoulder potential, revealing different melting behaviors at low and high densities.

Contribution

It provides a detailed phase diagram for a 2D system with repulsive shoulder interactions, highlighting the transition types across densities.

Findings

Low-density melting follows the KTHNY scenario.

High-density melting involves a first-order transition.

The phase diagram delineates different melting regimes.

Abstract

In the framework of the density functional theory of freezing proposed in our previous works, we calculate the phase diagram of two-dimensional system of particles interacting through the repulsive shoulder potential. This potential consists of the hard core and repulsive shoulder of the larger radius. It is shown that at low densities the system melts through the continuous transition in accordance with the Kosterlitz-Thouless-Halperin-Nelson-Young (KTHNY) scenario, while at high densities the conventional first order transition takes place.