Boson Peak decouples from elasticity in glasses with low connectivity

Abstract

We perform molecular-dynamics simulations of the vibrational and the elasto-plastic properties of polymeric glasses and crystals and corresponding atomic systems. We evidence that the elastic scaling of the density of states in the low-frequency boson peak (BP) region is different in crystals and glasses. Also, we see that the BP of the polymeric glass is nearly coincident with the one of the atomic glasses, thus revealing that the former - differently from elasticity - is controlled by non-bonding interactions only. Our results suggest that the interpretation of the BP in terms of macroscopic elasticity, discussed in highly connected systems, does not hold for systems with low connectivity.

arXiv commentaccepted on Physical Review Letters

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Cited by in corpus (7)

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• Unified theory of vibrational spectra in amorphous materials
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• Boson peak, elasticity, and glass transition temperature in polymer glasses: Effects of the rigidity of chain bending
• Understanding the scaling of boson peak through insensitivity of elastic heterogeneity to bending rigidity in polymer glasses
• Open and anisotropic soft regions in a model polymer glass