Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 11: Topical Session Glass Dynamics IV

MM 11.2: Topical Talk

Montag, 22. März 2010, 16:30–17:00, H16

A structural origin of cooperativity in supercooled liquids. — •Emanuela Del Gado — ETH Zürich, Switzerland

It is still debated whether and how the onset of cooperative dynamics in supercooled liquids approaching the glass transition can take place without any straightforward connection to structural changes. We have investigated the response to static deformation of the inherent structures (IS) of supercooled liquids, by using numerical simulations of model glass formers subject to deformations, combined with local energy minimization [1]. At low temperature, where the slow cooperative dynamics arise, non-affine rearrangements of the inherent structures allow to detect the presence of large correlated domains [2]. We propose that these non-affine domains are the IS counterpart of the cooperatively rearranging regions in the dynamics, and their presence supports the connections with elastic heterogeneity found in amorphous solids. Starting from these ideas, we quantitatively study the extent of spatial correlations of non-affine rearrangements in the IS and extract a static length-scale significantly growing in the temperature range where the dynamics become strongly cooperative [3]. Our analysis indicate a new, structural signature of glass transition.

[1] H. C. Oettinger, Phys. Rev. E 74, 011113 (2006).

[2] E. Del Gado, P. Ilg, M. Kroeger and H.C. Oettinger, Phys. Rev. Lett. 101, 095501 (2008).

[3] M. Mosayebi, P. Ilg, E. Del Gado and H.C. Oettinger, in preparation.