Skip to content

The Devil is in the details: Pentagonal bipyramids and dynamic arrest

Research output: Contribution to journalArticle

Original languageEnglish
Number of pages20
JournalJournal of Statistical Mechanics: Theory and Experiment
DOIs
DateAccepted/In press - 23 Oct 2019
DatePublished (current) - 2 Jan 2020

Abstract

Colloidal suspensions have long been studied as a model for atomic and molecular systems, due to the ability to fluorescently label and individually track each particle, yielding particle-resolved structural information. This allows various local order parameters to be probed that are otherwise inaccessible for a comparable molecular system. For phase transitions such as crystallisation, appropriate order parameters which emphasise 6-fold symmetry are a natural choice, but for vitrification the choice of order parameter is less clear cut. Previous work has highlighted the importance of icosahedral local structure as the glass transition is approached. However, counting icosahedra or related motifs is not a continuous order parameter in the same way as, for example, the bond-orientational order parameters Q6 and W6. In this work we investigate the suitability of using pentagonal bipyramid membership, a structure which can be assembled into larger, five-fold symmetric structures, as a finer order parameter to investigate the glass transition. We explore various structural and dynamic properties and show that this new approach produces many of the same findings as simple icosahedral membership, but we also find that large instantaneous displacements are often correlated with significant changes in pentagonal bipyramid membership, and unlike the population of defective icosahedra, the pentagonal bypyramid membership and spindle number do not saturate for any measured volume fraction, but continues to increase.

    Research areas

  • colloidal glasses, glasses (colloidal, polymer, etc.), glasses (structural), slow relaxation, glassy dynamics, aging

Documents

Documents

  • Full-text PDF (accepted author manuscript)

    Rights statement: This is the author accepted manuscript (AAM). The final published version (version of record) is available online via IOP Publishing at https://iopscience.iop.org/article/10.1088/1742-5468/ab5369 . Please refer to any applicable terms of use of the publisher.

    Accepted author manuscript, 6.77 MB, PDF document

    Embargo ends: 2/01/21

    Request copy

DOI

View research connections

Related faculties, schools or groups