The 3rd East Asia Joint Seminar on Statistical Physics
Structural origin of fractional Stokes-Einstein relation in glass-forming liquids
SPEAKER | Limei Xu
INSTITUTE | Peking University
DATE | October 16(Fri), 2015
TIME | 12:00
PLACE | Rm 1503(Bldg#I,5th), Korea Institute for Advanced Study, South Korea
ABSTRACT | In many glass-forming liquids, Fractional Stokes-Einstein relation (SER) is observed after the
breakdown of SER above glass transition. As of yet, the origin of such phenomenon remains
inclusive. Using molecular dynamics simulations, we investigate the breakdown of SER and
the onset of fractional SER in a model of metallic glass-forming liquid. We find that SER
breaks down when the size of the largest cluster consisting of trapped atoms starts to increase
sharply at which the largest cluster spans half of the simulations box along one direction, and
the fractional SER starts to follows when the largest cluster percolates the entire system and
forms stable 3-dimentional network structures. Further analysis based on the percolation theory
also confirms that percolation occurs at the onset of the fractional SER. Our results directly
link the breakdown of the SER with structure inhomogeneity and onset of the fraction SER
with percolation of largest clusters, thus provide a possible picture for the breakdown of SER
and onset of fractional SER in glass-forming liquids, which is important for the understanding
of dynamic properties in glass-forming liquids.
Keywords: Fractional Stokes-Einstein relation, dynamic heterogeneity, structural
heterogeneity, metallic glasses
1. L. Xu, F. Mallamace, Z. Yan, F. W. Starr, S. V. Buldyrev, H. E. Stanley, Nature Physics 5, 565(2009).
2. S. Pan, Z. Wu, W. Wang, M. Li, L. Xu, (Under Review).