Browsing by Author "Mladek, Bianca M"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Open Access Phase coexistence of cluster crystals: Beyond the gibbs phase rule(Physical Review Letters, 2007-12-07) Mladek, Bianca M; Charbonneau, Patrick; Frenkel, DaanWe report a study of the phase behavior of multiple-occupancy crystals through simulation. We argue that in order to reproduce the equilibrium behavior of such crystals, it is essential to treat the number of lattice sites as a constraining thermodynamic variable. The resulting free-energy calculations thus differ considerably from schemes used for single-occupancy lattices. Using our approach, we obtain the phase diagram and the bulk modulus for a generalized exponential model that forms cluster crystals at high densities. We compare the simulation results with existing theoretical predictions. We also identify two types of density fluctuations that can lead to two sound modes and evaluate the corresponding elastic constants. © 2007 The American Physical Society.Item Open Access Reentrant and isostructural transitions in a cluster-crystal former.(Phys Rev Lett, 2010-12-10) Zhang, Kai; Charbonneau, Patrick; Mladek, Bianca MWe study the low-temperature behavior of a simple cluster-crystal forming system through simulation. We find the phase diagram to be hybrid between the Gaussian core model and the penetrable sphere model. The system additionally exhibits S-shaped doubly reentrant phase sequences as well as critical isostructural transitions between crystals of different average lattice site occupancy. Because of the possible annihilation of lattice sites and accompanying clustering, the system moreover shows an unusual softening upon compression.