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Acoustic damping in Li$_2$O-2B$_2$O$_3$ glass observed by inelastic x-ray and optical Brillouin scattering

B. Rufflé·G. Guimbretière·E. Courtens·R. Vacher·G. Monaco
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Abstract

The dynamic structure factor of lithium-diborate glass has been measured at several values of the momentum transfer $Q$ using high resolution inelastic x-ray scattering. Much attention has been devoted to the low $Q$-range, below the observed Ioffe-Regel crossover \qco{}$\simeq$ 2.1 nm$^{-1}$. We find that below \qco{}, the linewidth of longitudinal acoustic waves increases with a high power of either $Q$, or of the frequency $Ω$, up to the crossover frequency \OMco{} $\simeq$ 9 meV that nearly coincides with the center of the boson peak. This new finding strongly supports the view that resonance and hybridization of acoustic waves with a distribution of rather local low frequency modes forming the boson peak is responsible for the end of acoustic branches in strong glasses. Further, we present high resolution Brillouin light-scattering data obtained at much lower frequencies on the same sample. These clearly rule out a simple $Ω^2$-dependence of the acoustic damping over the entire frequency range.

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B. Rufflé, G. Guimbretière, E. Courtens, R. Vacher, G. Monaco. 2005-10-27. Acoustic damping in Li$_2$O-2B$_2$O$_3$ glass observed by inelastic x-ray and optical Brillouin scattering. https://doi.org/10.1016/j.jnoncrysol.2006.01.120

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