Tuesday, July 23, 2013

1307.5516 (Alex Malins et al.)

Investigating Isomorphs with the Topological Cluster Classification    [PDF]

Alex Malins, Jens Eggers, C. Patrick Royall
Isomorphs are lines in the density-temperature plane of certain "strongly-correlating" liquids where two-point structure and dynamics have been shown to be close to identical up to a scale transformation. Here we consider such a strongly-correlating Lennard-Jones glassformer and investigate the behavior along isomorphs of higher-order structure and dynamics. We then consider an inverse power law reference system mapped to the Lennard-Jones system. Using the topological cluster classification to identify higher-order structures, in both systems we find bicapped square anti-prisms, which are known to be a locally favored structure in the Lennard-Jones glassformer. The population of these locally favored structures are up to 80% higher in the Lennard-Jones system than the equivalent inverse power law system. The structural relaxation time of the two systems, on the other hand, is almost indentical, and the four-point dynamical susceptibility is marginally higher in the inverse power law system. Upon cooling the lifetime of the locally favored structures in the Lennard-Jones system increases by up to 40% relative to the reference system. This indicates that the identification of clusters provides us with a sensitive measure for the investigation of local structure, and its relationship with glassy dynamics.
View original: http://arxiv.org/abs/1307.5516

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