The role of fivefold symmetry in suppressing crystallization | Nature Communications ### Subjects - Phase transitions and critical phenomena - Self-assembly - Statistical mechanics ## Abstract Although long assumed to have an important role in the suppression of crystallization and the development of glassformers, the effect of local fivefold symmetry has never been directly tested. Here we consider whether such suppression of crystallization has a kinetic or thermodynamic nature and investigate its mechanism. We introduce a model in which the degree of fivefold symmetry can be tuned by favouring arrangements of particles in pentagonal bipyramids. We thus show that fivefold symmetry has both kinetic and thermodynamic effects on the mechanism of crystallization to a face-centred cubic crystal. Our results suggest that the mechanism of crystallization suppression is related to the surface tension between fluid and crystal. Interestingly, the degree of fivefold symmetry has little effect on crystal growth rate, suggesting that growth may be only weakly coupled to fluid structure in hard sphere like systems. Upon increasing the fivefold symmetry, we find a first-order transition to

# Why don't marbles naturally arrange themselves like a crystal? - Tags: solid-state-physics, crystals - Score: 24 - Views: 8,880 - Answers: 8 - Asked by: user342326 (369 rep) - Asked on: Nov 25, 2018 - Last active: Nov 27, 2018 - License: CC BY-SA 4.0 --- ## Question Most solids are crystalline in nature because the energy released during the formation of ordered structure is more than that released during the formation of disordered structure such that the crystalline state is the lower energy state. So if we take different marbles in a box and shake it then shouldn't they arrange themselves in order to get to a low energy state? But we see they arrange in a disorderly way. Why do different phenomenon occur in these two cases? --- ## Answer 1 — Score: 33 - By: GiorgioP-DoomsdayClockIsAt-85 (42,332 rep) - Answered on: Nov 25, 2018 Interaction between marbles is very similar to the hard sphere (HS) interaction model i.e. a pair-wise potential energy which is zero if spheres do not overlap and $+\\infty$ elsewhere. Hard spheres are one of the first systems studied via computer simulation and one of the first big surprise was that by increasing pressure, they are able to cry

Identity crisis in alchemical space drives the entropic colloidal glass transition | Nature Communications ### Subjects ## Abstract 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. ### Emerging exotic compo