Jeudi 30 juin
Résumé :
Beyond the Gibbs Phase Rule : Study of a Cluster-Crystal Former.
Soft mesoscopic colloidal particles immersed in a microscopic solvent can at
times show effective pair interactions that are bounded and purely repulsive.
These interactions typically result either in reentrant melting upon compression,
as observed for the Gaussian core model (GCM), or the formation
of multiply-occupied (cluster) crystals in systems whose potentials are more
harshly repulsive. Our study of a model thought to belong to the latter family,
but the development of novel simulation techniques and of expanded thermodynamic
relations reveal the model’s behavior to be much richer. In addition to
clustering, the system exhibits S-shaped doubly reentrant phase sequences and
critical isostructural transitions between crystals of different lattice site occupancy.
Because of the possible annihilation of lattice sites and accompanying
clustering, the system moreover shows an unusual softening upon compression.
RECRUTEMENT ACCES DIRECT
Le département de physique
Fête de la Science 2018 