Breakdown of the Stokes–Einstein relation in Lennard-Jones glassformingmixtures with different interaction potential

摘要

The breakdown of the Stokes–Einstein relation was investigated for three glass-forming modelscomposed of mixtures of Lennard-Jones A-B particles, which have been constructed by modifyingthe shape of the interaction potential between A particles. By performing molecular dynamicssimulations, we show that these mixtures intrinsically possess different organizations. Thebreakdown of the Stokes–Einstein relation particularly occurs at different temperatures for each type of particles and it is directly related to the dynamical decoupling between A and B particles and theformation or not of paths where fast particles show jumplike motions. The effective size of each particles and the fraction of slow and fast particles were also determined. Similarity with silicateglasses including mixed alkali effect is discussed.