Dresden 2014 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 38: Glasses and Glass Transition - Part II (joint session CPP/ DY/DF)
DY 38.1: Hauptvortrag
Donnerstag, 3. April 2014, 15:00–15:30, ZEU 114
Microscopic investigation of creep in glasses — Tatjana Sentjabrskaja1, Pinaki Chaudhuri2, Wilson Poon3, Jürgen Horbach2, Stefan Egelhaaf1, and •Marco Laurati1 — 1Condensed Matter Physics Laboratory, Heinrich Heine University, Düsseldorf, Germany — 2Theoretische Physik II, Heinrich Heine University, Düsseldorf, Germany — 3SUPA and COSMIC, The University of Edinburgh, United Kingdom
The microscopic origin of the creep rheological response of colloidal glasses is investigated, based on the particle-level dynamics measured by confocal microscopy during application of a step stress. Sub-diffusive single-particle dynamics are the microscopic signature of creep. At a more local scale enhanced dynamic activity is observed at random locations, with the number of active regions following the time-dependence of the macroscopic strain. Instead, diffusive dynamics characterise the flowing system, with a transient super-diffusive regime during the onset of flow. Transient super-diffusion coincides with the appearance of enhanced dynamics in a specific region of the system, which subsequently rapidly expands and finally spans the whole system when the steady state of flow is reached.