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Updated: Jul 6, 2026
06:37
Analyzing Melts and Fluids from Ab Initio Molecular Dynamics Simulations with the UMD Package
Published on: September 17, 2021
Structural and dynamical heterogeneity in deeply supercooled liquid silicon.
1Research Institute for Computational Sciences (RICS), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan. t-morishita@aist.go.jp
Summary
In deeply supercooled liquid silicon, intermittent tetrahedral structures cause heterogeneous dynamics and anomalous relaxation. This structural and dynamical heterogeneity is significantly weaker in moderately supercooled silicon.
Area of Science:
- Condensed Matter Physics
- Materials Science
- Computational Chemistry
Background:
- Supercooled liquids exhibit complex structural and dynamical behaviors.
- Silicon's phase transitions and liquid states are crucial for semiconductor applications.
Purpose of the Study:
- Investigate structural and dynamical heterogeneity in supercooled liquid silicon.
- Understand the origins of anomalous relaxation in deeply supercooled silicon.
- Evaluate the Stillinger-Weber potential's accuracy at low temperatures.
Main Methods:
- First-principles molecular-dynamics simulations.
- Analysis of structural configurations (tetrahedrality).
- Assessment of dynamical heterogeneity and temporal fluctuations.
Main Results:
- Highly tetrahedral configurations form intermittently in deeply supercooled silicon (1000 K).
- Spatially heterogeneous dynamics and anomalous structural relaxation (stretched-exponential) are observed.
- Temporal fluctuations exhibit a 1/f power spectral density.
- Heterogeneity is significantly reduced in moderately supercooled silicon (1600 K).
Conclusions:
- Intermittent tetrahedrality drives heterogeneity and anomalous relaxation in supercooled silicon.
- The degree of heterogeneity depends strongly on the supercooling level.
- The Stillinger-Weber potential's validity in deeply supercooled regimes requires careful consideration.
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