The correlation factor of impurity diffusion in diamond lattice was re-examined for the general case where the vacancy-impurity binding gave rise to different jump frequencies in different directions for a vacancy at the second coordination sites. Manning's expression was disputed. A formal derivation of an expression was given for the special case where the jump frequency of the vacancy at the second coordination sites was independent of its jump direction, which result was then identical with the expression given by Manning. The correlation factor for the general case was not obtainable analytically, and was computed numerically for an assumed model of vacancy-impurity binding. An expression for an upper limit of the correlation factor in the general case with a positive binding energy was also given and discussed, which became a lower limit for the case with a negative binding energy. These results were then compared with Manning's general expression.

Correlation Factor of Impurity Diffusion in Diamond Lattice. Hu, S.M.: Physical Review, 1969, 177[3], 1334-40