{"title":"Crossover in atomic mobility underlying the glass transition in inorganic glasses.","authors":"Cillian Cockrell, Robin W Grimes","doi":"10.1088/1361-648X/ad9fc8","DOIUrl":null,"url":null,"abstract":"<p><p>While the glass transition is easy to identify macroscopically, the underlying atomic mechanisms which facilitate the transition from amorphous solid to fluid are still poorly understood. We conduct classical molecular dynamics simulations on a variety of inorganic glasses in order to identify these mechanisms. While also modelling larger systems, we find that the essential qualities which constitute a glass and its transition to a liquid are present even in systems containing only a few hundred atoms. The transition is therefore a local phenomenon. Atomic mobility, the ability of an atom to escape its local coordination environment, is identified as a universal marker of the glass transition. In the solid state, the fraction of mobile atoms is mobile, whereas in the liquid state, effectively all atoms are mobile. The glass transition is continuous between these limiting states, with half of the network forming atoms attaining mobility exactly at the glass transition temperature, over a specific mobility half life, informed by thermodynamics. Over time, network forming atoms which were immobile may swap to become mobile and vice versa, though the population of mobile atoms remains a half.</p>","PeriodicalId":16776,"journal":{"name":"Journal of Physics: Condensed Matter","volume":" ","pages":""},"PeriodicalIF":2.3000,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Physics: Condensed Matter","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1088/1361-648X/ad9fc8","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, CONDENSED MATTER","Score":null,"Total":0}
引用次数: 0
Abstract
While the glass transition is easy to identify macroscopically, the underlying atomic mechanisms which facilitate the transition from amorphous solid to fluid are still poorly understood. We conduct classical molecular dynamics simulations on a variety of inorganic glasses in order to identify these mechanisms. While also modelling larger systems, we find that the essential qualities which constitute a glass and its transition to a liquid are present even in systems containing only a few hundred atoms. The transition is therefore a local phenomenon. Atomic mobility, the ability of an atom to escape its local coordination environment, is identified as a universal marker of the glass transition. In the solid state, the fraction of mobile atoms is mobile, whereas in the liquid state, effectively all atoms are mobile. The glass transition is continuous between these limiting states, with half of the network forming atoms attaining mobility exactly at the glass transition temperature, over a specific mobility half life, informed by thermodynamics. Over time, network forming atoms which were immobile may swap to become mobile and vice versa, though the population of mobile atoms remains a half.
期刊介绍:
Journal of Physics: Condensed Matter covers the whole of condensed matter physics including soft condensed matter and nanostructures. Papers may report experimental, theoretical and simulation studies. Note that papers must contain fundamental condensed matter science: papers reporting methods of materials preparation or properties of materials without novel condensed matter content will not be accepted.