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A spherical model with directional interactions: II. Dynamics and landscape properties.
Christian Mayer1, Francesco Sciortino, Piero Tartaglia
1Dipartimento di Fisica, Università di Roma La Sapienza, Piazzale Aldo Moro 2, I-00185 Rome, Italy.
Summary
This study explores a binary mixture of hard spheres, revealing how specific interactions promote tetrahedral structures. Simulations show an ideal gel forming and transitioning to an attractive glass as density increases.
Area of Science:
- Soft matter physics
- Computational chemistry
- Materials science
Background:
- Binary hard-sphere mixtures are fundamental models in statistical mechanics.
- Understanding phase behavior and structural ordering is crucial for materials design.
- Tetrahedral ordering can arise from specific inter-particle potentials.
Purpose of the Study:
- To investigate the phase behavior and dynamics of a binary non-additive hard-sphere mixture.
- To explore the formation of equilibrium structures with tetrahedral ordering.
- To analyze the relationship between structure, dynamics, and the potential energy landscape.
Main Methods:
- Event-driven molecular dynamics simulations were extensively performed.
- Iso-diffusivity lines were mapped in the phase diagram.
- Statistical properties of the potential energy landscape were evaluated.
Main Results:
- The system exhibits tetrahedral ordering for specific inter-particle potential parameters.
- An ideal gel phase was observed, transitioning to an attractive glass with increasing density.
- Configurational entropy was found to be finite in the ground state within the network-forming region, showing logarithmic energy dependence.
Conclusions:
- The study elucidates the complex phase behavior of a binary non-additive hard-sphere mixture.
- The observed transition from ideal gel to attractive glass highlights the role of density and interactions.
- The findings offer insights into the relationship between energy, entropy, and structure in disordered materials.
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