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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 13: Glasses and Glass Transition (joint session CPP/DY)
CPP 13.2: Vortrag
Montag, 18. März 2024, 16:45–17:00, H 0107
Dynamics and Timescales of Higher Order Correlations in Supercooled Colloidal Systems — •Nele N. Striker1, Irina Lokteva1,2, Michael Dartsch1,2, Francesco Dallari1, Claudia Goy1, Fabian Westermeier1, Verena Markmann1, Svenja C. Hövelmann1, Gerhard Grübel1,2, and Felix Lehmkühler1,2 — 1Deutsches Elektronen-Synchrotron DESY, Hamburg, Germany — 2The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany
There has been extensive research into the nature of the glass transition, however its mechanisms remain mostly unclear. Recent works show that long-living locally favored structures (LFS), such as icosahedral structures forming upon supercooling, may play a key role. We show results from a combined X-ray Photon Correlation Spectroscopy (XPCS) and X-ray Cross Correlation Analysis (XCCA) experiment on colloidal hard spheres in the vicinity of the glass transition [1]. We defined a new correlation function g_c probing the timescales of higher-order correlations by tracking the time evolution of the structural higher-order correlations within the sample. We observed an increase in the ratio of the relaxation times of g_c and the standard individual particle relaxation time from about 0.4 to 0.9. The increasing values suggest that the local orders within the sample are becoming more long-lived approaching the glass transition. These results indicate that not only the presence but also the lifetime of LFS grows close to the glass transition.
[1] N. Striker et al., J. Phys. Chem. Lett., 2023, 14(20), 4719-4725
Keywords: Glass Transition; Photon Correlation Spectroscopy; Colloidal Systems