Compressing nearly hard sphere fluids increases glass fragility

Ludovic Berthier (1) , Thomas A. Witten (2)

1 LCVN - Laboratoire des colloïdes, verres et nanomatériaux
2 University of Chicago

We use molecular dynamics to investigate the glass transition occurring at large volume fraction, phi, and low temperature, T, in assemblies of soft repulsive particles. We find that equilibrium dynamics in the (phi, T) plane obey a form of dynamic scaling in the proximity of a critical point at T=0 and phi=phi_0, which should correspond to the ideal glass transition of hard spheres. This glass point, 'point G', is distinct from athermal jamming thresholds. A remarkable consequence of scaling behaviour is that the dynamics at fixed phi passes smoothly from that of a strong glass to that of a very fragile glass as phi increases beyond phi_0. Correlations between fragility and various physical properties are explored.

Domaines: Mécanique statistique [cond-mat.stat-mech]; Systèmes désordonnés et réseaux de neurones [cond-mat.dis-nn]

Ludovic Berthier, Thomas A. Witten. Compressing nearly hard sphere fluids increases glass fragility. EPL - Europhysics Letters, 2009, 86, pp.10001. ⟨10.1209/0295-5075/86/10001⟩. ⟨hal-00597624⟩