Laboratoire Charles Coulomb UMR 5221 CNRS/UM2 (L2C)

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Accueil > La Recherche > Axes & Equipes > Matière Molle & Verres > Equipe : Physique des Verres > Thème : Structure, vibration, relaxations dans les systèmes désordonnés

Thème : Structure, vibration, relaxations dans les systèmes désordonnés

Présentation

In the last years important progress has been made on long-standing fundamental questions such as those related to sound properties in glasses and their relation with the universal low-temperature anomalies. A comprehensive picture of the nontrivial frequency dependence of sound attenuation in oxide glasses can now be proposed. It is controlled by three processes which in increasing order of the frequency at which they dominate are : the thermal relaxation of defects, relaxation via anharmonic interactions with the thermal bath, and a remarkably rapid increase (α Ω4) towards a Ioffe-Regel crossover at THz frequencies which we have evidenced in two oxide glasses. The latter mechanism relates to the boson peak and the low temperature plateau generally observed in the thermal conductivity. The close relation between the Ioffe-Regel crossover and the boson peak implies a resonance of these rather local low-lying optic modes with acoustic modes near the Ioffe-Regel limit.

Current researches

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Dernières publications

+ Viscosity of silica and doped silica melts: evidence for a crossover temperature doi link

Auteur(s): Mauro John C., Kurkjian Charles r., Gupta Prabhat K., Kob W.

(Article) Publié: Journal Of The American Ceramic Society, vol. p.0 (2021)

 
+ Dynamics of Nanoparticles in Polydisperse Polymer Networks: from Free Diffusion to Hopping doi link

Auteur(s): Sorichetti V., Hugouvieux Virginie, Kob W.

(Article) Publié: Macromolecules, vol. 54 p.8575-8589 (2021)
Texte intégral en Openaccess : arxiv

 
+ Direct Structural Evidence for Interfacial Gradients in Asymmetric Polymer Nanocomposite Blends doi link

Auteur(s): Genix A.-C.(Corresp.), Bocharova Vera, Carroll Bobby, Dieudonne-George P., Sztucki Michael, Schweins Ralf, Sokolov Alexei p., Oberdisse J.

(Article) Publié: Acs Appl. Mater. Interfaces, vol. 13 p.36262-36274 (2021)

 

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Innovative experimental setups

Brillouin light scattering (BLS)
We constructed a unique High Resolution Brillouin Spectrometer with the highest precision on acoustic phonon frequencies and linewidth worldwide. It consists of (...)

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