Temperature behavior of tracer diffusion in amorphous materials: A random-walk approach

Limoge, Yves; Jl, Bocquet

doi:10.1103/physrevlett.65.60

Cited by 74 publications

(31 citation statements)

References 6 publications

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“…From the distribution of activation energies, it is not possible to extract directly an estimate of the diffusion barrier although theoretical work by Limoge and Bocquet 18 suggests that the effective activation energy should be around the maximum of its distribution. In our case, this provides a ball-park figure of about 5 eV.…”

Section: Energetics and Spatial Extentmentioning

confidence: 99%

Elementary mechanisms governing the dynamics of silica

Mousseau

Barkema

Leeuw

2000

The Journal of Chemical Physics

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A full understanding of glasses requires an accurate atomistic picture of the complex activated processes that constitute the low-temperature dynamics of these materials. To this end, we generate over five thousand activated events in a model silica glass, using the activation-relaxation technique; these atomistic mechanisms are analyzed and classified according to their activation energies, their topological properties and their spatial extent. We find that these are collective processes, involving ten to hundreds of atoms with a continuous range of activation energies; that diffusion and relaxation occurs through the creation, annihilation and motion of single dangling bonds; and that silicon and oxygen have essentially the same diffusivity.

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Section: Energetics and Spatial Extentmentioning

confidence: 99%

Elementary mechanisms governing the dynamics of silica

Mousseau

Barkema

Leeuw

2000

The Journal of Chemical Physics

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“…where d is the system dimensionality (d = 1,2,3) and |r(t) − r(0)| 2 is the average squared displacement of particles in time t, [13]. In this study, all simulations were done at a constant temperature of 300 K, using a box with 20 3 bcc Fe unit cells, unless stated otherwise.…”

Section: Diffusion Model and Parametrisationmentioning

confidence: 99%

Theoretical evaluation of the role of crystal defects on local equilibrium and effective diffusivity of hydrogen in iron

Bombač

Katzarov

Pashov

et al. 2017

Materials Science and Technology

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Hydrogen diffusion and trapping in ferrite is evaluated by quantum mechanically informed kinetic Monte Carlo simulations in defective microstructures. We find that the lattice diffusivity is attenuated by two to four orders of magnitude due to the presence of dislocations. We also find that pipe diffusivity is vanishingly small along screw dislocations and demonstrate that dislocations do not provide fast diffusion pathways for hydrogen as is sometimes supposed. We make contact between our simulations and the predictions of Oriani's theory of 'effective diffusivity', and find that local equilibrium is maintained between lattice and trap sites. We also find that the predicted effective diffusivity is in agreement with our simulated results in cases where the distribution of traps is spatially homogeneous; in the trapping of hydrogen by dislocations where this condition is not met, the Oriani effective diffusivity is in agreement with the simulations to within a factor of two. ARTICLE HISTORY

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“…Non-Arrhenius character is observed for hydrogen diffusivity in amorphous TiCuH 1.41 and Zr 2 PdH x alloys [7][8][9][10]. The origin of these observations is not yet fully understood despite many models developed to resolve it [11][12][13][14][15][16][17][18][19][20]. The plausible model is in terms of the presence of numerous and diverse sites in amorphous matrix; whereby, it follows a broad continuous distribution of site and transition energies (DSATE).…”

Section: Introductionmentioning

confidence: 97%

“…Because the ab-initio calculation is limited only to several hundred particles [20][21][22], the classical model using the pair inter-atomic potentials is still an effective way to deal with many problems in material science. Hence the systematic study of diffusion on the model with the pair effective potentials between impurity and host atoms could shed new light on the diffusion mechanism in AMAs.…”

Section: Introductionmentioning

confidence: 99%