Dynamic heterogeneity in an orientational glass

Abstract

Family of compounds CBr${}_n$Cl${}_{4-n}$ has been proven helpful in unraveling microscopic mechanisms responsible of glassy behavior. Some of the family members show translational ordered phases with minimal disorder which appears to reveal glassy features, thus deserving special attention in the search for universal glass anomalies. In this work, we studied CBrCl${}_3$ dynamics by performing extensive molecular dynamics simulations. Molecules of this compound perform reorientational discrete jumps, where the atoms exchange equivalent positions among each other revealing a cage-orientational jump motion fully comparable to the cage-rototranslational jump motion in supercooled liquids. Correlation times were calculated from rotational autocorrelation functions showing good agreement with previous reported dielectric results. From mean waiting and persistence times calculated directly from trajectory results, we are able to explain which microscopic mechanisms lead to characteristic times associated with $\alpha$ and $\beta$-relaxation times measured experimentally. We found that two nonequivalent groups of molecules have a longer characteristic time than the other two nonequivalent groups, both of them belonging to the asymmetric unit of the monoclinic (C2/c) lattice.

References in corpus (11)

• Glassy dynamics of kinetically constrained models
• Excitation lines and the breakdown of Stokes-Einstein relations in supercooled liquids
• Pinning dependent field driven domain wall dynamics and thermal scaling in an ultrathin Pt/Co/Pt magnetic film
• Evolution in complex systems
• Dynamic phase coexistence in glass-forming liquids
• $\alpha$- and $\beta$- Relaxation Dynamics of a fragile plastic crystal
• Cage Size and Jump Precursors in Glass-Forming Liquids: Experiment and Simulations
• Thermodynamic and kinetic fragility of Freon113: the most fragile plastic crystal
• Out-of-equilibrium relaxation of the Edwards-Wilkinson elastic line
• Connecting short and long time dynamics in hard-sphere-like colloidal glasses
• Role of structure in the alpha and beta dynamics of a simple glass-forming liquid

Cited by in corpus (1)

• Emergence of glassy features in halomethane crystals