First principles impurity diffusion coefficients

We report the prediction of impurity diffusion coefficients entirely from first principles, using density-functional theory (DFT) calculations. From DFT we obtain all microscopic parameters in the pre-factor and activation energy of impurity diffusion coefficients: (i) the correlation factor through a five frequency model, (ii) the impurity jump frequency within the framework of transition state theory and (iii) the free energies of vacancy formation and vacancy-solute binding. Specifically, we calculate the impurity diffusion coefficients of Mg, Si and Cu in dilute face-centered cubic Al alloys. The results show excellent agreement with experimental data. We discuss the factors contributing to the trends in diffusivities of these impurities.