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

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Physics

Background:

• Phase field crystal (PFC) models are crucial for simulating material microstructures.
• Existing PFC models often struggle to capture the full range of phase transitions, especially involving vapor phases.
• Thermodynamic consistency and control over system pressure/volume are vital for realistic simulations.

Purpose of the Study:

• To introduce a novel phase field crystal (PFC) type theory.
• To incorporate the complete spectrum of solid-liquid-vapor phase transitions.
• To achieve thermodynamic consistency and enable control over system pressure and volume.

Main Methods:

• Development of a new PFC theory utilizing a single density order parameter.
• Demonstration of equilibrium properties and thermodynamic consistency in pressure-volume-temperature (PVT) space.
• Implementation of methods for controlling system volume or pressure.
• Conducting nonequilibrium simulations to observe phase transitions.

Main Results:

• The presented PFC theory quantitatively models equilibrium properties of pure substances.
• Full consistency with thermodynamics in PVT space is achieved.
• Simulations demonstrate the capability for 2- and 3-phase growth (solid, liquid, vapor).
• The formalism allows for a comprehensive study of pressure-induced transformations.

Conclusions:

• The new PFC theory successfully models a wide range of phase transitions using a single order parameter.
• It provides a robust framework for studying pressure-driven interactions between condensed phases and vapor.
• This model fills a critical gap in existing PFC theories, enabling new experimental and computational research avenues.