Regensburg 2007 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 13: Glass I (joint session with DF)
DY 13.4: Vortrag
Dienstag, 27. März 2007, 10:45–11:00, H23
Liquid-to-glass transition of bulk-glass forming Cu60Ti20Zr20 alloy by molecular dynamics simulations — •Xiujun Han1,2 and Helmar Teichler1 — 1Inst. f. Materials Physics, University of Göttingen — 2IFF, Forschungszentrum Jülich
The present work reports results from molecular dynamics studies about microscopic structure and dynamics of the ternary, bulk metallic glass forming Cu60Ti20Zr20. In detail we consider nearest neighbour numbers, specific heat, simulated glass temperature, diffusion coefficients, and the incoherent intermediate scattering function (ISF). The applied atomic model reproduces well experimental X-ray data of total radial distribution function. It provides for Cu60Ti20Zr20 a structure with marked intermediate range order. The incoherent ISFs are analyzed within an extension of the mode coupling theory (MCT), where the memory kernel is evaluated from Laplace transform of the ISF. The dynamics of the system fulfils in most respects the predictions of the MCT, up to a suppression of the algebraic t−a-decay in the early β-range, which is traced back to effects of single particle vibrations in the effective memory kernel that are not fully included in the MCT. As by-product, our investigation provides a method to re-construct, around the critical temperature, major parts of the memory kernel from λ and the plateau-value of the ISF.