Berlin 2012 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 11: Glasses II (with CPP, talks by DY)

DY 11.6: Vortrag

Dienstag, 27. März 2012, 11:15–11:30, MA 004

Microscopic picture of the beta-wing in simulated Ni0.5Zr0.5 melt — •Helmar Teichler — Inst. f. Materialphysik, Univ. Göttingen, Göttingen, Germany

The beta-wing is found in a large variety of liquids as an additional contribution to the susceptibility on the high frequency flank of the alpha peak. The underlying microscopic processes are not well understood so far. Regarding this, we have analyzed simulation data of a Ni0.5Zr0.5 model, using as main tool the fraction of un-displaced particles (FUDP). In the alpha and beta regime, the FUDP is a nearly linear mapping of the incoherent intermediate scattering function (ISF) (for suitably q) (H. Teichler, PRL, 107,067801 (2011)). Hence, the susceptibilities of FUDP and ISF display nearly identical alpha peak and beta-wing. The analysis unambiguously shows that this susceptibility is due to temporal accumulation of incoherent short-ranged displacement processes, where the stretched exponential behavior reflects "structure conserving correlations" in the accumulation process. Accordingly, the beta-wing reflects stronger structure restoring effects in the wing range than in the rest of the alpha regime.