Self-diffusion and impurity diffusion in oxides

1980 ◽  
Vol 15 (4) ◽  
pp. 803-824 ◽  
Author(s):  
R. Freer
Keyword(s):  
Impurity Diffusion ◽  
Self Diffusion

Tracer Impurity Diffusion in Liquid Metals: K in Na and Na in K

1973 ◽  
Vol 28 (1) ◽  
pp. 117-119
Author(s):  
T. Persson ◽  
S. J. Larsson
Keyword(s):  
Liquid Metals ◽  
Activation Energies ◽  
Impurity Diffusion ◽  
Effective Activation ◽  
Kcal Mole ◽  
Self Diffusion

The diffusivities of 42K in Na and of 24Na in K have been measured between 100 ° and 285 °C, utilizing an „infinite capillary" technique. The results are adequately described by the Arrhenius relations (in cm2/s) DK in Na = 0.46 · 10-3 exp (-1.82/RT) and DNa in K = 0.93 · 10-3 exp (-2.11/RT). The differences ΔQ in effective activation energies between impurity diffusion and self-diffusion are about -0.4 kcal/mole for Na and +0.1 kcal/mole for K. This can be satisfactorily explained by electrostatic screening arguments. The impurity diffuses slower than the host atoms in Na, faster in K.

Pressure and Strain Effects on Diffusion

1989 ◽  
Vol 163 ◽  
Author(s):  
A. Antonelli ◽  
J. Bernholc
Keyword(s):  
Hydrostatic Pressure ◽  
Formation Energy ◽  
Defect Formation ◽  
Nearest Neighbors ◽  
Diffusion Barriers ◽  
Impurity Diffusion ◽  
Strain Effects ◽  
Self Diffusion ◽  
Lattice Matched

AbstractWe have investigated, via parameter-free calculations, the effects of hydrostatic and nonhydrostatic strains on the energetics of defect formation and self-diffusion in silicon. The three microscopic mechanisms, vacancy, interstitial, and concerted exchange, have very similar activation enthalpies at zero pressure but exhibit different behavior with hydrostatic pressure. Our results suggest that experiments performed at different pressures can determine the relative contributions of each of these mechanisms. The calculations also show that the neutral Si vacancy has a negative relaxation volume, with the nearest neighbors of the vacancy relaxing inwards, in contrast to the Si (111) surface. Large nonhydrostatic strains, which are present in e.g. Si/GexSi1-x pseudomorphic heterostractures, substantially reduce the formation energy of the tetrahedral interstitial, but do not affect the formation energy of the vacancy. These findings suggest that, aside from being another useful tool for the investigation of self-diffusion in Si, nonhydrostatic strain may significantly affect annealing and impurity diffusion in strained heterostructures. In particular, the interstitial-assisted impurity diffusion may proceed more rapidly in Si lattice-matched to GexSi1-x, but be slowed down in GexSi1-x lattice-matched to Si. The compressed GexSi1-x layers may thus act as diffusion barriers for impurities diffusing with help of native interstitials, such as B or P.

Notizen: Impurity Diffusion in Isotopic 6Li and 7Li Metal

1970 ◽  
Vol 25 (11) ◽  
pp. 1765 ◽  
Author(s):  
A. Ott ◽  
A. Lodding
Keyword(s):  
Quantum Effects ◽  
Impurity Diffusion ◽  
Self Diffusion

The mobilities of foreign metal tracers in isotopically pure lithium matrices have been studied. Differential diffusivities have been obtained for Na, Ag, Au, Zn and Ga in Li. The behaviour of impurities whose diffusion is not of a regular vacancy character (Au, Ag, Zn) appears connected with the quantum effects in Li self-diffusion.

Predicting Diffusion Coefficients from First Principles via Eyring’s Reaction Rate Theory

2009 ◽  
Vol 294 ◽  
pp. 1-13 ◽  
Author(s):  
Manjeera Mantina ◽  
Long Qing Chen ◽  
Zi Kui Liu
Keyword(s):  
First Principles ◽  
Diffusion Coefficients ◽  
Reaction Rate ◽  
Harmonic Approximation ◽  
Impurity Diffusion ◽  
Rate Theory ◽  
Simplified Approach ◽  
Self Diffusion ◽  
Reaction Rate Theory ◽  
Jump Frequencies

A simplified approach to predicting diffusion coefficients directly from first-principles is proposed. In this approach, the atomic jump frequencies are calculated through the Eyring’s reaction rate theory while the temperature dependence of diffusion coefficients are accounted using phonon theory within the quasi-harmonic approximation. The procedure can be applied to both self-diffusion and impurity diffusion coefficients and different crystal systems. Applications to self-diffusion coefficients in fcc Cu, bcc Mo, hcp Mg and impurity diffusion coefficients of Li in fcc Al, W in bcc Mo and Cd in hcp Mg show agreement with experimental measurements.

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