Accueil >
Production scientifique
(317) Production(s) de KOB W.
 |
Static and dynamic length scales in glass-forming systems
Auteur(s): Kob W.
(Séminaires)
Oak Ridge National Laboratory (Knoxville, US), 2012-06-05 |
|
|
Static and dynamic properties of sodium borosilicate liquids and glasses: insight from ab initio simulations
Auteur(s): Ispas S., Pedesseau L., Kob W.
Conference: International Conference on Advanced Materials Modelling (ICAMM) (Nantes, FR, 2012-06-13)
Résumé: We present a study of structural and dynamical properties of a liquid and glassy sodium borosilicate of composition 3Na2O-B2O3-6SiO2, study carried out using first principles molecular dynamics simulations. This glass composition is thus similar to the glass wool that is used in our daily life. The simulations were carried out within the DFT framework as implemented in the VASP code. The samples contained 320 atoms, which is rather demanding for ab initio calculations, but it has allowed to study the intermediate order in glasses. In particular, we have investigated how boron atoms integrate and modify the silica network.
Furthermore we have determined the vibrational properties and identified the contributions of the different species to the density of states. We found that 3- and 4-fold coordinated boron atoms give rise to specific features in the density of states. The infrared spectra of our glassy models is also presented and directly compared to experimental data.
|
|
Structural, dynamic and electronic properties of sodium-silicate
glasses and liquids from ab initio simulations
Auteur(s): Kob W.
Conférence invité: Annual Meeting of the Glass and Optical Materials Division (St. Louis, US, 2012-05-20)
|
|
|
|
Static point-to-set correlations in glass-forming liquids 
Auteur(s): Berthier L., Kob W.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 85 p.011102 (2012)
|
|
Computational Material Science
Auteur(s): Kob W.
Conférence invité: ModSysC2020 (Montpellier, FR, 2012-03-07)
|
|
|
|
Non-monotonic temperature evolution of dynamic correlations in glass-forming liquids
Auteur(s): Kob W., Roldan-Vargas Sandalo, Berthier L.
(Article) Publié:
Nature Physics, vol. 8 p.164-167 (2012)
Texte intégral en Openaccess : 
Ref HAL: hal-00667220_v1
Ref Arxiv: 1107.3928
DOI: 10.1038/nphys2133
WoS: 000300403700023
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
183 Citations
Résumé: The viscosity of glass-forming liquids increases by many orders of magnitude if their temperature is lowered by a mere factor of 2-3. Recent studies suggest that this widespread phenomenon is accompanied by spatially heterogeneous dynamics, and a growing dynamic correlation length quantifying the extent of correlated particle motion. Here we use a novel numerical method to detect and quantify spatial correlations that reveal a surprising non-monotonic temperature evolution of spatial dynamical correlations, accompanied by a second length scale that grows monotonically and has a very different nature. Our results directly unveil a dramatic qualitative change in atomic motions near the mode-coupling crossover temperature, which involves no fitting or indirect theoretical interpretation. These findings impose severe new constraints on the theoretical description of the glass transition, and open several research perspectives, in particular for experiments, to confirm and quantify our observations in real materials.
|
|
Static and Dynamic Length Scales in Glass-forming Liquids
Auteur(s): Kob W.
Conférence invité: Workshop on Computer Simulation Studies in Condensed Matter Physics (Athens, US, 2012-02-20)
|
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 
