Prof. Matthias Sperl "Glass-Glass-Transitions from Purely Repulsive Interactions"

In addition to the glass transition in the hard-sphere system,
transitions between different amorphous solid states are known for
systems with hard core plus short-ranged attraction. The dynamics in
the vicinity of such glass-glass transitions have been worked out in
detail in theory and tested in experiments and simulation. The
established understanding of such transitions is given by a
competition of repulsive and attractive length scales.

For the case of a competition between two repulsive length scales, the
glass-transition scenarios are surprisingly rich: In addition to a
reentry at constant packing fraction indicating melting by cooling, i.e.,
a sequence of glass-liquid-glass -- for increased pressure at constant
temperature the sequence liquid-glass-liquid-glass is obtained which is
corresponding to a diffusion anomaly in the liquid state. Beyond these
reentry phenomena, not only one but two glass-glass transition lines are
predicted and explained by the interplay of two different length scales.

Specific calculations are presented for a square-shoulder system and
are considered relevant for colloidal suspensions, certain metals, and
water.

References:
- Disconnected Glass-Glass Transitions and Diffusion Anomalies in a Model
with Two Repulsive Length Scales, Phys. Rev. Lett. 104, 145701 (2010).
- Multiple Glass Singularities and Isodynamics in a Core-Softened
Model for Glass-Forming Systems, Phys. Rev. Lett. 113, 258302 (2014).

invited by Prof. Eckhard Bartsch