Solid-solid transitions induced by repulsive interactions revisited

Area of Science:

• Condensed Matter Physics
• Statistical Mechanics
• Computational Physics

Background:

• Revisiting 15-year-old research on isostructural solid-solid transitions.
• Focusing on classical systems with Stell-Hemmer potentials and repulsive interactions.

Purpose of the Study:

• Obtain the full phase diagram in the crystal region using perturbation theory.
• Test the performance of perturbation theory against computer simulations.
• Analyze isostructural phase transitions induced by repulsive forces.

Main Methods:

• Applying perturbation theory for classical solids.
• Utilizing Monte Carlo simulations to calculate crystal free-energy.
• Comparing theoretical phase diagrams with simulation results.

Main Results:

• The perturbation theory correctly identifies stable face-centered cubic (fcc) and body-centered cubic (bcc) phases.
• The theory predicts special points: a coexistence point and critical points for isostructural transitions.
• Quantitative predictions for some phase diagram features, with less accuracy for the bcc phase.

Conclusions:

• Perturbation theory offers a valuable tool for understanding solid-solid transitions.
• Discrepancies in bcc phase predictions highlight the need for improved reference system representations.
• The study validates computational methods for phase diagram determination.