Contribution of the terahertz vibrations to the high temperature thermal conductivity of vitreous silica

Giacomo Baldi (1) , Elisa Fabiani (2) , Aldo Fontana (3, 4) , Valentina Giordano (5) , Giulio Monaco (5) , Giancarlo Ruocco (4, 6) , Francesco Sette (5)

1 INFM-CNR CRS-SOFT Operative Group in Grenoble
2 DTBS - Département Microtechnologies pour la Biologie et la Santé
3 Physics
4 INFM-CNR CRS-SOFT
5 ESRF - European Synchrotron Radiation Facility
6 Physics

A combined inelastic X-rays and neutron scattering experiment is performed on the prototypical glass vitreous silica. The complementarity of the two techniques is exploited to determine the dynamic structure factor in a wide range of energies and wave-vectors. The vibrational modes spectral density is then used to compute the high temperature thermal conductivity. The acoustic-like modes persisting at THz frequencies are shown to represent a relevant heat conduction channel, although they cannot account for the entire thermal conductivity.

Mots clés: Physical Sciences

Giacomo Baldi, Elisa Fabiani, Aldo Fontana, Valentina Giordano, Giulio Monaco, et al.. Contribution of the terahertz vibrations to the high temperature thermal conductivity of vitreous silica. Philosophical Magazine, 2008, 88 (33-35), pp.3915-3923. ⟨10.1080/14786430802438192⟩. ⟨hal-00513965⟩