Comparing dynamic correlation lengths from an approximation to the four-point dynamic susceptibility and from the picosecond vibrational dynamics

Abstract

Recently a new approach to the determination of dynamic correlation lengths, ξ, for supercooled liquids, based on the properties of the slow (picosecond) vibrational dynamics, was carried out [L. Hong, V.N. Novikov, and A.P. Sokolov, Phys. Rev. E 83, 061508 (2011)]. Although these vibrational measurements are typically conducted well below the glass transition temperature, Tg, the assumption is that the structure of the liquid is frozen at Tg, so that the ξ characterize dynamic heterogeneity in the supercooled liquid state. We compare ξ from this method to values calculated using an approximation to the four-point dynamic susceptibility. For 26 different materials we find good correlation between the two measures; moreover, the pressure dependences are consistent within the large experimental error. However, ξ from Boson peak measurements above Tg have a different, and unrealistic, temperature dependence.

10 pages, 3 figures

References in corpus (2)

• Spatial correlations in the dynamics of glassforming liquids: Experimental determination of their temperature dependence
• Spontaneous and induced dynamic fluctuations in glass-formers I: General results and dependence on ensemble and dynamics

Cited by in corpus (4)

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• Revealing the Link between Structural Relaxation and Dynamic Heterogeneity in Glass-Forming Liquids
• Dynamic heterogeneity of glass-forming liquids in the density scaling regime
• The glass susceptibility: growth kinetics and saturation under shear