Crystallization of hard spheres within ellipsoidal confinement

Area of Science:

• Materials Science
• Computational Physics
• Chemical Engineering

Background:

• Understanding crystallization in confined geometries is crucial for designing advanced materials and nanoscale devices.
• The influence of boundary curvature on crystallization dynamics remains an active area of research.

Purpose of the Study:

• To investigate the effects of ellipsoidal cavity curvature anisotropy on the nucleation and growth of hard sphere crystals.
• To elucidate the relationship between surface geometry and the resulting crystalline structure and defect distribution.

Main Methods:

• Event-driven molecular dynamics simulations were employed to model hard sphere crystallization.
• Analysis focused on nucleation sites, growth patterns, free energy scaling, and defect distribution on curved surfaces.

Main Results:

• Crystallization initiates at low-curvature regions and propagates inward, with dynamics governed by boundary curvature.
• Prolate ellipsoids yield multiple misoriented domains, while oblate ellipsoids favor a nearly monocrystalline structure.
• Nucleation free energy scales linearly with cluster size, and particle-free energy shows a power-law dependence on Gaussian curvature.

Conclusions:

• Confining boundary curvature anisotropy is a key factor controlling crystallization in ellipsoidal cavities.
• Curvature-induced defect localization dictates the symmetry breaking and final crystalline structure.
• Findings provide insights into controlling crystal formation in curved nanoconfinement for materials design.