Long-lived non-equilibrium interstitial solid solutions in binary mixtures
Ioatzin Ríos de Anda1, Francesco Turci1, Richard P Sear2
1H.H. Wills Physics Laboratory, Tyndall Ave., Bristol BS8 1TL, United Kingdom.
The Journal of Chemical Physics
|October 2, 2017
Summary
Particle crystallization in two-component hard sphere mixtures forms interstitial solid solutions. Small particles get trapped in large particle lattices, creating long-lived non-equilibrium structures, unlike equilibrium predictions.
Area of Science:
- Materials Science
- Physical Chemistry
- Computational Physics
Background:
- Crystallization of multi-component systems is crucial for materials design.
- Understanding particle interactions and lattice formation is key to predicting material properties.
- Previous studies on hard sphere mixtures focused on equilibrium properties.
Purpose of the Study:
- To investigate the heterogeneous crystallization of two-component hard sphere mixtures.
- To compare experimental results with molecular dynamics simulations.
- To elucidate the formation of non-equilibrium structures in such systems.
Main Methods:
- Particle-resolved experimental studies.
- Molecular dynamics simulations of homogeneous nucleation.
- Analysis of final crystalline assemblies and particle site occupancy.
Main Results:
- Both experiments and simulations show interstitial solid solutions with large particles forming close-packed lattices.
- Small particles occupy octahedral holes, forming long-lived non-equilibrium structures.
- Small particle occupancy reaches a maximum of ~14%, independent of concentration, and no further hopping is observed.
Conclusions:
- The crystallization process leads to non-equilibrium structures due to trapped small particles.
- Observed structures differ from previously predicted equilibrium interstitial solutions.
- The maximum occupancy of small particles is a significant finding for understanding mixture crystallization.
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