Relationship between Structure and Dynamics of an Icosahedral Quasicrystal using Unsupervised Machine Learning

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Main Authors: Bedolla-Montiel, Edwin A., Marín-Aguilar, Susana, Dijkstra, Marjolein
Format: Preprint
Published: 2025
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author Bedolla-Montiel, Edwin A.
Marín-Aguilar, Susana
Dijkstra, Marjolein
author_facet Bedolla-Montiel, Edwin A.
Marín-Aguilar, Susana
Dijkstra, Marjolein
contents We present a comprehensive study of the structure, formation, and dynamics of a one-component model system that self-assembles into an icosahedral quasicrystal (IQC). Using molecular dynamics simulations combined with unsupervised machine learning techniques, we identify and characterize the unique structural motifs of IQCs, including icosahedral and dodecahedral arrangements, and quantify the evolution of local environments during the IQC formation process. Our analysis reveals that the formation of the IQC is driven by the emergence of distinct local clusters that serve as precursors to the fully developed quasicrystalline phase. Additionally, we examine the dynamics of the system across a range of temperatures, identifying transitions from vibrationally restricted motion to activated diffusion, and uncovering signatures of dynamic heterogeneity inherent to the quasicrystalline state. To directly connect structure and dynamics, we use a machine-learning-based order parameter to quantify the presence of distinct local environments across temperatures. We find that regions with high structural order, as captured by specific machine-learned classes, correlate with suppressed self-diffusion and minimal dynamical heterogeneity, consistent with phason-like motion within the IQC. In contrast, regions with lower structural order exhibit enhanced collective motion and increased dynamical heterogeneity. These results establish a quantitative framework for understanding the coupling between structural organization and dynamical processes in quasicrystals, providing new insights into the mechanisms governing IQC stability and dynamics.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15731
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Relationship between Structure and Dynamics of an Icosahedral Quasicrystal using Unsupervised Machine Learning
Bedolla-Montiel, Edwin A.
Marín-Aguilar, Susana
Dijkstra, Marjolein
Soft Condensed Matter
We present a comprehensive study of the structure, formation, and dynamics of a one-component model system that self-assembles into an icosahedral quasicrystal (IQC). Using molecular dynamics simulations combined with unsupervised machine learning techniques, we identify and characterize the unique structural motifs of IQCs, including icosahedral and dodecahedral arrangements, and quantify the evolution of local environments during the IQC formation process. Our analysis reveals that the formation of the IQC is driven by the emergence of distinct local clusters that serve as precursors to the fully developed quasicrystalline phase. Additionally, we examine the dynamics of the system across a range of temperatures, identifying transitions from vibrationally restricted motion to activated diffusion, and uncovering signatures of dynamic heterogeneity inherent to the quasicrystalline state. To directly connect structure and dynamics, we use a machine-learning-based order parameter to quantify the presence of distinct local environments across temperatures. We find that regions with high structural order, as captured by specific machine-learned classes, correlate with suppressed self-diffusion and minimal dynamical heterogeneity, consistent with phason-like motion within the IQC. In contrast, regions with lower structural order exhibit enhanced collective motion and increased dynamical heterogeneity. These results establish a quantitative framework for understanding the coupling between structural organization and dynamical processes in quasicrystals, providing new insights into the mechanisms governing IQC stability and dynamics.
title Relationship between Structure and Dynamics of an Icosahedral Quasicrystal using Unsupervised Machine Learning
topic Soft Condensed Matter
url https://arxiv.org/abs/2507.15731