New density functional approach for solid-liquid-vapor transitions in pure materials

TL;DR

This paper introduces a novel phase field crystal model that accurately captures solid-liquid-vapor transitions in pure materials, enabling detailed thermodynamic and non-equilibrium studies of phase interactions under various pressures.

Contribution

A new PFC-type theory that models all three phases with a single density parameter and aligns with thermodynamics, including methods to control volume or pressure.

Findings

Quantitative agreement with thermodynamics in phase behavior

Simulation of multi-phase growth and transformations

Capability to study pressure-driven phase interactions

Abstract

A new phase field crystal (PFC) type theory is presented, which accounts for the full spectrum of solid-liquid-vapor phase transitions within the framework of a single density order parameter. Its equilibrium properties show the most quantitative features to date in PFC modelling of pure substances, and full consistency with thermodynamics in pressure-volume-temperature space is demonstrated. A method to control either the volume or the pressure of the system is also introduced. Non-equilibrium simulations show that 2 and 3-phase growth of solid, vapor and liquid can be achieved, while our formalism also allows for a full range of pressure-induced transformations. This model opens up a new window for the study of pressure driven interactions of condensed phases with vapor, an experimentally relevant paradigm previously missing from phase field crystal theories.