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Published on: December 4, 2017
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The stability of many-body systems
1Division of Chemistry, School of Biomedical and Molecular Sciences, University of Surrey, Guildford GU2 7XH, UK.
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|February 14, 2017
Summary
Many common potentials used in condensed matter physics are thermodynamically unstable. This study identifies parameter ranges for potential stability, revealing issues with widely used models like exponential-6.
Area of Science:
- Condensed matter physics
- Statistical mechanics
- Computational modeling
Background:
- Analytic potential forms are crucial for modeling condensed matter systems.
- Thermodynamic stability is a fundamental property determining system behavior.
- Previous work has not systematically assessed the stability of common potentials.
Purpose of the Study:
- To determine the thermodynamic stability ranges for analytic potential forms used in condensed matter theory.
- To identify specific parameter values leading to stable, unstable, or uncertain system behavior.
- To validate theoretical stability predictions with molecular dynamics simulations.
Main Methods:
- Application of Fisher and Ruelle (1966) pair interaction stability criteria.
- Systematic analysis of simple analytic potential forms from the literature.
- Molecular dynamics simulations for the double Gaussian potential in stable and unstable regimes.
Main Results:
- Defined parameter ranges for thermodynamic stability, instability, and uncertainty for various potentials.
- Demonstrated thermodynamic instability in many-particle systems using common exponential-6 and Born-Mayer-Huggins potentials for alkali halides.
- Molecular dynamics simulations corroborated theoretical stability predictions.
Conclusions:
- Many widely used potentials in condensed matter modeling are thermodynamically unstable.
- The Fisher-Ruelle criteria provide a robust method for assessing potential stability.
- Careful selection of potential parameters is essential for reliable condensed matter simulations.
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