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Elastic constant dishomogeneity and $Q^2$ dependence of the broadening of the dynamical structure factor in disordered systems

M. Montagna·G. Ruocco·G. Viliani·R. Di Leonardo·R. Dusi·G. Monaco·M. Sampoli·T. Scopigno
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Abstract

We propose an explanation for the quadratic dependence on the momentum $Q$, of the broadening of the acoustic excitation peak recently found in the study of the dynamic structure factor of many real and simulated glasses. We ascribe the observed $Q^2$ law to the spatial fluctuations of the local wavelength of the collective vibrational modes, in turn produced by the dishomegeneity of the inter-particle elastic constants. This explanation is analitically shown to hold for 1-dimensional disordered chains and satisfatorily numerically tested in both 1 and 3 dimensions.

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M. Montagna, G. Ruocco, G. Viliani, R. Di Leonardo, R. Dusi, G. Monaco, M. Sampoli, T. Scopigno. 1998-09-23. Elastic constant dishomogeneity and $Q^2$ dependence of the broadening of the dynamical structure factor in disordered systems. https://doi.org/10.1103/physrevlett.83.3450

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