title: Sound attenuation at terahertz frequencies and the boson peak of vitreous silica.
abstract: The propagation and damping of the acoustic excitations in vitreous silica is measured at terahertz frequencies using inelastic x-ray scattering. The apparent sound velocity shows a marked dispersion with frequency while the sound attenuation undergoes a crossover from a fourth to a second power law frequency dependence. This finding solves a recent controversy concerning the location of this crossover in vitreous silica, clarifying that it occurs at the position of the glass-characteristic excess of vibrational modes known as boson peak, and thus establishing a direct connection between boson peak and acoustic dispersion curves.
authors.affiliation: European Synchrotron Radiation Facility, BP220, 38043 Grenoble, France. giacomo.baldi@esrf.fr
authors.forename: G
authors.initials: G
authors.lastname: Baldi
authors.forename: V M
authors.initials: VM
authors.lastname: Giordano
authors.forename: G
authors.initials: G
authors.lastname: Monaco
authors.forename: B
authors.initials: B
authors.lastname: Ruta