Slow dynamics of a confined supercooled binary mixture: direct space analysis

Dynamical properties of a Lennard-Jones binary mixture embedded in an off-lattice matrix of soft spheres are studied in the direct space upon supercooling by molecular dynamics simulations. On lowering the temperature, the smaller particles tend to avoid the soft sphere interfaces and correspondingly their mobility decreases below one of the larger particles. The system displays a dynamic behavior, consistent with the mode coupling predictions. A decrease in the mode coupling crossover temperature with respect to the bulk is found. We however find that the range of validity of the theory shrinks with respect to the bulk. This is due to the change in the smaller particle mobility and to a substantial enhancement of hopping processes well above the crossover temperature upon confinement.