Releasing frustration for better relaxation
Dr. Francesco Turci (University of Bristol)

Among the most enduring pictures of dynamic arrest is that liquids form geometric motifs upon supercooling. In Euclidean space, such system-specific motifs are incompatible with a crystalline structure and give rise to a frustrated, slow dynamics. However, it is possible (at least in computer simulations) to promote the growth of locally ordered regions based on the preferred geometric motifs in two ways: i) slightly modifying the composition of the liquids or ii) slightly perturbing the curvature of the space the liquids are embedded in.

We explore these two routes to control frustration in two atomistic models of glass formers and find that slow dynamics is very robust to both the two kinds of perturbations. In particular, we find that while for weak frustration the collective behaviour of the system is dominated by the presence of geometric motifs, for large frustration the dynamical slowing down occurs on scales much larger than the extent of the geometric domains, suggesting that other mechanisms come into play.