Applicability of dynamic facilitation theory to binary hard disk systems
Abstract
We investigate numerically the applicability of dynamic facilitation (DF) theory for glass-forming binary hard disk systems where supercompression is controlled by pressure. By using novel efficient algorithms for hard disks, we are able to generate equilibrium supercompressed states in an additive non-equimolar binary mixture, where micro-crystallization and size segregation do not emerge at high average packing fractions. Above an onset pressure where collective heterogeneous relaxation sets in, we find that relaxation times are well described by a "parabolic law" with pressure. We identify excitations, or soft-spots, that give rise to structural relaxation, and find that they are spatially localized, their average concentration decays exponentially with pressure, and their associated energy scale is logarithmic in the excitation size. These observations are consistent with the predictions of DF generalized to systems controlled by pressure rather than temperature.
Cite
@article{arxiv.1604.02621,
title = {Applicability of dynamic facilitation theory to binary hard disk systems},
author = {Masaharu Isobe and Aaron S. Keys and David Chandler and Juan P. Garrahan},
journal= {arXiv preprint arXiv:1604.02621},
year = {2016}
}
Comments
6 pages, 3 figures, to appear in Phys. Rev. Lett