First-principles calculations of impurity diffusion activation energies in Al

We present first-principles density functional theory calculations of the diffusion activation energies of Mg, Si, and the $3d$ transition metals Sc--Zn in Al. In general, the calculated activation energies are underestimated with respect to experiments by 5--25%. The trend seen in experiments, namely, that impurities around Ti, V, and Cr have high diffusion activation energies leading to ``anomalously'' slow diffusion, is well reproduced in the present calculations. We provide an explanation in terms of electrostatic screening effects.