Regensburg 2004 – wissenschaftliches Programm
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DF: Dielektrische Festkörper
DF 4: Gl
äser II (gemeinsam FV DF/DY)
DF 4.3: Vortrag
Dienstag, 9. März 2004, 15:15–15:30, H23
Dynamical heterogeneities in simulated amorphous Ni0.5Zr0.5: correlations with density and order parameter fluctuations — •Imad Ladadwa and Helmar Teichler — Institut für Materialphysik, and SFB 602, Universität Göttingen
Dynamical heterogeneity is a fundamental aspect of particle motion in supercooled liquids and glasses. For metallic alloy system, a great part of the information on dynamical heterogeneity comes from computer simulations, leaving open so far, however, a detailed answer concerning the origin of heterogeneity. In order to approach this question, we have carried out molecular dynamics simulations for an amorphous Ni0.5Zr0.5 model, generating well relaxed structures at 700, 760, and 810 K, that means well below the dynamical glass temperature Tc = 1120 K. From analyzing long-time simulations over 0.7 µ s for medium size systems (N=5184, periodic boundary conditions), we find striking interrelationship between spatial fluctuations of the atomic mobility, that means dynamical heterogeneity, and of the fluctuation of topological order and of the chemical composition in the system. The results indicate an anti-correlation between local Ni content and Ni atoms mobility, on the one hand, and a correlation between the local order and the Ni mobility on the other hand. The talk will present the definitions of suitable measuring tools for these quantities and quantitative estimates for the inherent correlations.