It had been proposed previously that, for the activation energy for impurity diffusion in the diamond lattice to be smaller than that for self diffusion, there must exist a long-range vacancy-impurity interaction potential. The present work explored, more quantitatively, certain required characteristics of such a potential. The relationship between the activation energies of impurity diffusion, QA, and self-diffusion, QB, was approximately given by QA ≈ QB-u(r3), where u(r3) was the potential when the vacancy was at the third coordination site of the impurity atom. Most known physical interaction models did not satisfy the required characteristics of u(r); thus leaving that of the extended vacancy as the probable one. Regardless of the interaction potential, the relationship between the migration energies of the simple vacancy, Hv, and the vacancy-impurity complex, Hc, was simply given by Hv = Hc + QB-QA-Eb, where Eb was the binding energy.

On Interaction Potential, Correlation Factor, Vacancy Mobility, and Activation Energy of Impurity Diffusion in Diamond Lattice. Hu, S.M.: Physica Status Solidi B, 2006, 60[2], 595–604