Journal Article

PreJuSER-17547

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Transport properties and Stokes-Einstein relation in a computer-simulated glass-forming Cu_33.3Zr_66.7 melt

Han, X. J.FZJ* ; Schober, H. R.FZJ*

2011
APS College Park, Md.

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Please use a persistent id in citations: http://hdl.handle.net/2128/10906  doi:10.1103/PhysRevB.83.224201

Abstract: Molecular dynamics simulation with a modified embedded atom potential was used to study transport properties and the Stokes-Einstein relation of a glass-forming Cu33.3Zr66.7 metallic melt. Upon cooling, at high temperatures, the self-diffusion coefficients of the two species evolve nearly parallel, whereas they diverge below 1600 K. The viscosity as function of temperature is calculated from the Green-Kubo equation. The critical temperature of mode coupling theory T-c is found as 1030 K, from both the transport properties and the alpha-relaxation time. It is found that the Stokes-Einstein relation between viscosity and diffusivity breaks down at around 1600 K, far above T-c and even above the melting temperature. The temperature dependence of the effective diameter in the Stokes-Einstein relation correlates closely with the first derivative of the ratio of the self-diffusion coefficients of the two components. We propose that the onset of Stokes-Einstein relation breakdown could be predicted quantitatively by the divergence behavior of diffusion coefficients, and the breakdown of Stokes-Einstein relation is ascribed to the sudden increase of the dynamic heterogeneity.

Keyword(s): J

Note: We are grateful to A. Meyer and J. Horbach for their comments and suggestions. Financial supports from the National Natural Science Foundation of China (Grant Nos. 50371043 and 50890174), Shanghai Municipal Natural Science Foundation (Grant No. 10ZR1415700), and Research Fund for the Doctoral program of Higher Education of China (Grant No. 20100073120008) are acknowledged.

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Contributing Institute(s):

1. Theoretische Nanoelektronik (PGI-2)

Research Program(s):

1. Grundlagen für zukünftige Informationstechnologien (P42)

Appears in the scientific report 2011

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