Non-ergodicity transition and multiple glasses in binary mixtures: on the accuracy of the input static structure in the mode coupling theory

• Published in: Journal of physics. Condensed matter Vol. 24; no. 32; pp. 325106, 1 - 325106
• Main Authors: Tchangnwa Nya, F, Ayadim, A, Germain, Ph, Amokrane, S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 15.08.2012; Institute of Physics
• Subjects: Asymmetry; Closures; Condensed matter; Condensed matter: structure, mechanical and thermal properties; Correlation; Density; Equations of state, phase equilibria, and phase transitions; Exact sciences and technology; Glass transitions; Joining; Mathematical analysis; Mathematical models; Physics; Specific phase transitions; Autocorrelation function; Glass transition; Percus-Yevick equation; Mode coupling; Asymmetry; Glass; Chemical composition; Correlation functions; Binary mixtures; Pair distribution function; Ornstein-Zernike equation; Hard-sphere model
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/24/32/325106

We examine the question of the accuracy of the static correlation functions used as input in the mode coupling theory (MCT) of non-ergodic states in binary mixtures. We first consider hard-sphere mixtures and compute the static pair structure from the Ornstein-Zernike equations with the Percus-Yevick closure and more accurate ones that use bridge functions deduced from Rosenfeld's fundamental measures functional. The corresponding MCT predictions for the non-ergodicity lines and the transitions between multiple glassy states are determined from the long-time limit of the density autocorrelation functions. We find that while the non-ergodicity transition line is not very sensitive to the input static structure, up to diameter ratios D2 D1 = 10, quantitative differences exist for the transitions between different glasses. The discrepancies with the more accurate closures become even qualitative for sufficiently asymmetric mixtures. They are correlated with the incorrect behavior of the PY structure at high size asymmetry. From the example of ultra-soft potential it is argued that this issue is of general relevance beyond the hard-sphere model.