Anomalous phase behavior in a model fluid with only one type of local structure

Area of Science:

• Condensed Matter Physics
• Materials Science
• Statistical Mechanics

Background:

• Anomalous phase behaviors in particle systems are often attributed to the coexistence of multiple particle sizes.
• Understanding the fundamental requirements for such behaviors is crucial for materials design and theoretical physics.

Purpose of the Study:

• To investigate whether multiple particle populations are necessary for anomalous phase behaviors.
• To explore the role of interparticle potential softening in inducing unconventional features.

Main Methods:

• Simulations of systems with spherically symmetric unbounded potentials.
• Analysis of interparticle repulsion and its effect on particle separation.
• Observation of phase transitions, including melting and polymorphism.

Main Results:

• Concurrent existence of multiple particle diameters is not required for anomalous phase behaviors.
• A weak softening of interparticle repulsion can lead to a single nearest-neighbor separation.
• This softening induces reentrant melting, solid polymorphism, and thermodynamic, dynamic, and structural anomalies.

Conclusions:

• Anomalous phase behavior can arise from a single particle population interacting via a softened potential.
• The findings expand the range of systems capable of exhibiting unconventional phase behaviors.
• This research challenges existing prerequisites for observing complex phase transitions in particle systems.