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Updated: Feb 4, 2026

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Atom Probe Tomography Studies on the CuIn,GaSe2 Grain Boundaries
Published on: April 22, 2013
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Machine learning determination of atomic dynamics at grain boundaries.
Tristan A Sharp1, Spencer L Thomas2, Ekin D Cubuk3
1Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104; tsharp@sas.upenn.edu.
Summary
Machine learning reveals a structural property called "softness" that predicts atomic rearrangement in polycrystalline materials. This finding helps understand atomic dynamics in grain boundaries, crucial for material properties.
Area of Science:
- Materials Science
- Computational Materials Science
- Condensed Matter Physics
Background:
- Grain boundaries in polycrystalline materials are critical for atomic motion but complex to analyze.
- Linking local atomic structure to dynamics in grain boundaries remains a challenge.
Purpose of the Study:
- To establish a connection between local structure and atomic dynamics in polycrystalline materials using machine learning.
- To identify a structural descriptor that quantifies the propensity of atoms to rearrange.
Main Methods:
- Utilized a machine learning technique to analyze atomic structures and dynamics.
- Defined a purely structural quantity, 'softness', to capture atomic rearrangement potential.
- Applied the method to polycrystalline materials, including crystalline regions, stacking faults, twin boundaries, and grain boundaries.
Main Results:
- The 'softness' metric successfully distinguished between low-rearrangement regions (crystalline, stacking faults, twin boundaries) and high-variability grain boundaries.
- Atomic rearrangement probability showed an Arrhenius-like behavior for a given softness.
- Identified a decrease in the prefactor for low-softness atoms, indicating entropy's dominant role in grain boundary dynamics.
Conclusions:
- Machine learning provides a powerful tool to link local structure and atomic dynamics in complex materials.
- 'Softness' is a predictive structural descriptor for atomic rearrangements in polycrystalline materials.
- Entropy variations significantly influence atomic dynamics within grain boundaries.
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