Dresden 2009 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 9: Glass II

DF 9.4: Vortrag

Dienstag, 24. März 2009, 15:00–15:20, WIL B321

Glass-Transition Scenarios for the Square-Shoulder System — •Matthias Sperl — Institut für Materialphysik im Weltraum, DLR, Koeln

It was discovered recently that the competition of two mechanisms of glassy arrest can trigger glass-glass transitions if the two glasses are sufficiently distinct in their localization length. It was found in simulation and experiment that the interplay between hard-sphere repulsion and a short-ranged attraction can exhibit such a scenario. Here the competition between two repulsive length scales is considered. While for both very low and very high shoulders the hard-sphere limit is recovered, for specific widths and heights of the shoulder one can identify higher-order glass-transition singularities that are indicative of glass-glass transitions. In addition, multiple reentry scenarios are found: glass-liquid-glass transitions are possible both for constant density as well as for constant temperature. The results for the square-shoulder glass transition (and its generalizations) are expected to be relevant in micellar, metallic, and granular systems as well as in water.

This work is done in collaboration with E. Zaccarelli, F. Sciortino, P. Kumar, and H. E. Stanley.