Applied Physics Program, University of Michigan, Ann Arbor, MI, 48109, USA.
Department of Physics, University of Michigan, Ann Arbor, MI, 48109, USA.
Nat Commun. 2019 Jan 8;10(1):64. doi: 10.1038/s41467-018-07977-2.
A universally accepted explanation for why liquids sometimes vitrify rather than crystallize remains hotly pursued, despite the ubiquity of glass in our everyday lives, the utilization of the glass transition in innumerable modern technologies, and nearly a century of theoretical and experimental investigation. Among the most compelling hypothesized mechanisms underlying glass formation is the development in the fluid phase of local structures that somehow prevent crystallization. Here, we explore that mechanism in the case of hard particle glasses by examining the glass transition in an extended alchemical (here, shape) space; that is, a space where particle shape is treated as a thermodynamic variable. We investigate simple systems of hard polyhedra, with no interactions aside from volume exclusion, and show via Monte Carlo simulation that glass formation in these systems arises from a multiplicity of competing local motifs, each of which is prevalent in-and predictable from-nearby ordered structures in alchemical space.
尽管玻璃在我们日常生活中无处不在，玻璃化转变在无数现代技术中得到了广泛应用，并且已经进行了近一个世纪的理论和实验研究，但对于液体有时会形成玻璃态而不是结晶态的原因，仍然没有一个普遍接受的解释。在导致玻璃形成的最引人注目的假设机制中，是在流体相中发展出某种阻止结晶的局部结构。在这里，我们通过在扩展的化学（这里是形状）空间中检查玻璃化转变，来研究硬粒子玻璃中的这种机制；也就是说，将粒子形状视为热力学变量的空间。我们研究了硬多面体的简单体系，除了体积排斥之外没有相互作用，并通过蒙特卡罗模拟表明，这些体系中的玻璃形成是由多种相互竞争的局部图案引起的，每个图案都存在于化学空间中附近有序结构中，并且可以从这些结构中预测到。
