Sound attenuation and anharmonic damping in solids with correlated disorder

We study via self-consistent Born approximation a model for sound waves in a disordered environment, in which the local fluctuations of the shear modulus G are spatially correlated with a certain correlation length ξ. The theory predicts an enhancement of the density of states over Debye's ω2 l...

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Bibliographic Details
Date:2010
Main Authors: Schirmacher, W., Tomaras, C., Schmid, B., Baldi, G., Viliani, G., Ruocco, G., Scopigno, T.
Format: Article
Language:English
Published: Інститут фізики конденсованих систем НАН України 2010
Series:Condensed Matter Physics
Online Access:http://dspace.nbuv.gov.ua/handle/123456789/32096
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Journal Title:Digital Library of Periodicals of National Academy of Sciences of Ukraine
Cite this:Sound attenuation and anharmonic damping in solids with correlated disorder / W. Schirmacher, C. Tomaras, B. Schmid, G. Baldi, G. Viliani, G. Ruocco, T. Scopigno // Condensed Matter Physics. — 2010. — Т. 13, № 2. — С. 23606: 1-6. — Бібліогр.: 21 назв. — англ.

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Digital Library of Periodicals of National Academy of Sciences of Ukraine
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Summary:We study via self-consistent Born approximation a model for sound waves in a disordered environment, in which the local fluctuations of the shear modulus G are spatially correlated with a certain correlation length ξ. The theory predicts an enhancement of the density of states over Debye's ω2 law (boson peak) whose intensity increases for increasing correlation length, and whose frequency position is shifted downwards as 1/ξ. Moreover, the predicted disorder-induced sound attenuation coefficient Γ(k) obeys a universal scaling law ξ Γ(k) = f(kξ) for a given variance of G. Finally, the inclusion of the lowest-order contribution to the anharmonic sound damping into the theory allows us to reconcile apparently contradictory recent experimental data in amorphous SiO2.