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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Glasses and Glass Transition (joint session DY/CPP)

CPP 33.8: Vortrag

Montag, 16. März 2020, 17:15–17:30, ZEU 118

Aging of SiO₂: Scaling of Dynamic Heterogeneities and Cluster Analysis of Single Particle Jumps — •Katharina Vollmayr-Lee¹, Horacio E. Castillo², Christopher H. Gorman³, and Taylor S. Cookmeyer⁴ — ¹Bucknell University, Lewisburg, PA, USA — ²Ohio University, Athens, OH, USA — ³University of California, Santa Barbara, CA, USA — ⁴University of California, Berkeley, CA, USA

We study the aging dynamics of the strong glass former SiO₂ via molecular dynamics simulations. We quench the system from a high to a low temperature, and then investigate the dynamics of the system as a function of waiting time, the time elapsed since the quench. For a system of 336 atoms, we find that both the dynamic susceptibility and the probability distribution of the local incoherent intermediate scattering function can be described by simple scaling forms in terms of the global incoherent intermediate scattering function. We also find for the scaling of these dynamic heterogeneities that the aging dynamics is controlled by a unique aging clock which is the same for Si and O atoms. Furthermore, we present results for a system of 115248 atoms for which we use single particle trajectories to identify single particle jump events when a particle escapes its cage formed by its neighbors. To study how these jump events are correlated in space and time, we find clusters of jumping particles. We will present cluster size distributions of both simultaneously jumping particles, as well as space-time clusters (jump events which are neighbors in space and time).