Revealing the Link between Structural Relaxation and Dynamic Heterogeneity in Glass-Forming Liquids

Abstract

Despite the use of glasses for thousands of years, the nature of the glass transition is still mysterious. On approaching the glass transition, the growth of dynamic heterogeneity has long been thought to play a key role in explaining the abrupt slowdown of structural relaxation. However, it still remains elusive whether there is an underlying link between structural relaxation and dynamic heterogeneity. Here, we unravel the link by introducing a characteristic time scale hiding behind an identical dynamic heterogeneity for various model glass-forming liquids. We find that the time scale corresponds to the kinetic fragility of liquids. Moreover, it leads to scaling collapse of both the structural relaxation time and dynamic heterogeneity for all liquids studied, together with a characteristic temperature associated with the same dynamic heterogeneity. Our findings imply that studying the glass transition from the viewpoint of dynamic heterogeneity is more informative than expected.

Hidden Order Beyond Hyperuniformity in Critical Absorbing States

“…In the CLG and RO models, κ ex peaks at lengths that scale diverging at the transition, where the peak height also diverges. Likewise, in supercooled liquids, κ ex peaks at a time scaling with τ, and its peak value diverges at the transition [30]. Furthermore, the heterogeneities of the coarse-grained density at R ¼ ξ h observed in RO models, Fig 2(c), reflect that of the displacements of the particles at the relaxation time in supercooled liquids [24].…”

Universal behavior of the apparent fragility in ultraslow glass forming systems

“…Very recently, basing on the model numerical analysis of the vitrification process, Wang et al . 61 concluded: … We find that the time scale corresponds to the kinetic fragility of liquids . Moreover , it leads to scaling collapse of both the structural relaxation time and dynamic heterogeneity for all liquids studied , together with a characteristic temperature associated with the same dynamic heterogeneity… .’.…”

The critical model size for simulating the structure-dynamics correlation in bulk metallic glasses

“…Fig. 7d shows the maximum of non-Gaussian parameter α 2,max increases monotonously with the structural relaxation times τ α , which is reminiscent of the correlation between dynamic heterogeneity and dynamics slowdown [50,55]. Moreover, the existence of a general link between α 2,max and τ α can be perceived in terms of the collapse of curves for three systems with different sizes.…”

“…It had been comprehensively analyzed in supercooled liquids via experimental techniques and computational simulations [46][47][48][49]. Wang et al [50] reported a general correlation between the dynamic heterogeneity and relaxation time in a variety of model glass-forming liquids with pairwise potentials by using the identical dynamic heterogeneity condition, which was also confirmed in MG-forming systems [51] with many-body potentials. However, how the system size affects this correlation in the MG system is still unclear.…”