Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 14: Poster: Glasses I (jointly with DY)
CPP 14.1: Poster
Dienstag, 27. März 2012, 18:15–20:15, Poster A
Elastic Properties of Amorphous Solids — •Christian L. Klix, Florian Ebert, Georg Maret, and Peter Keim — University of Konstanz
In this contribution, we present experimental results on the elastic properties of a two-dimensional colloidal glass former. Given that glasses are solids, one expects a mechanical behavior similar to that of crystals, i.e., glasses exhibit a finite shear modulus µ. Using positional data from video microscopy, we study the displacement field and connect it to the dynamical matrix D(q) via the equipartition theorem [1]. The resulting dispersion relation of the system hints at structural change upon decreasing the temperature in the glassy state. Next, this data is used to derive the Lamé coefficients and the corresponding moduli from thermally excited modes in the long wavelength limit [1] using continuum elasticity theory. We consider finite size and time effects and find the expected frequency dependence of the shear modulus µ. By cooling the system, the significant increase of µ allows us to determine the glass transition temperature Tg precisely. Following the method described in [2], we compute the short wavelength excitations in our system and analyse the density of states as well as the structure of normal modes in a two-dimensional colloidal system.
H. H. Von Grünberg, P. Keim, and G. Maret, Phys. Rev. Lett. 93, 255703 (2004)
A. Gosh, V. K. Chikkadi, P. Schall, J. Kurchan, and D. Bonn, Phys. Rev. Lett. 104, 248305 (2010)