Weak temperature dependence of ageing of structural properties in atomistic model glassformers

T Jenkinson and P Crowther and F Turci and CP Royall, JOURNAL OF CHEMICAL PHYSICS, 147, 054501 (2017).

DOI: 10.1063/1.4994836

Ageing phenomena are investigated from a structural perspective in two binary Lennard-Jones glassformers, the Kob-Andersen and Wahnstrom mixtures. In both, the geometric motif assumed by the glassformer upon supercooling, the locally favoured structure ( LFS), has been established. The KobAndersen mixture forms bicapped square antiprisms; the Wahnstrom model forms icosahedra. Upon ageing, we find that the structural relaxation time has a time-dependence consistent with a power law. However, the LFS population and potential energy increase and decrease, respectively, in a logarithmic fashion. Remarkably, over the time scales investigated, which correspond to a factor of 10(4) change in relaxation times, the rate at which these quantities age appears almost independent of temperature. Only at temperatures far below the Vogel-Fulcher-Tamman temperature do the ageing dynamics slow. Published by AIP Publishing.

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