Berlin 2015 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 61: Focus: Disordered Systems, Glasses under Shear I (joint session CPP, DY)

CPP 61.4: Vortrag

Donnerstag, 19. März 2015, 10:30–10:45, C 243

Potential energy landscape analysis of sheared glass-forming systems — •Markus Blank-Burian and Andreas Heuer — Institut für Physikalische Chemie, WWU Münster, Deutschland

We performed molecular dynamics simulations of small binary Lennard-Jones mixtures (65 ≤ N ≤ 1040) under constant shear rates and at a very low temperature (T = 0.01). The shearing is achieved by applying Lees-Edwards periodic boundary conditions to the system.

In previous work on unsheared systems it was shown, that most of the physical properties of macroscopic systems are already encoded in these small systems. The dynamics of these small systems can be described by a continous time random walk (CTRW) between minima of the potential energy landscape (PEL). Our focus now lies on comparing these results with the constantly sheared system.

For the analysis of the sheared system, we perform energy minimization using the strain as an additional variable. We then use this information to identify inherent structures (IS) from the trajectories. These IS turn out to have zero strain. Thus, they are comparable to the unsheared system. From the resulting statistical data we hope to gain a microscopic understanding of macrorheological phenomena like the initial stress overshoot as well as the shear thinning in the plastic flow regime.