It was recalled that developments in electronic structure calculations, combined with advances in computer performance, had made it possible to perform ab initio calculations on various structural properties. The values of vacancy formation and migration enthalpies, which were calculated within the framework of density-functional theory in the local density approximation, agreed with experimental data to within less than 10%. Reliable self-diffusion coefficients for the vacancy mechanism could be deduced. This shed new light on the so-called self-diffusion anomaly in body-centered cubic metals. In particular, it highlighted the role played by structural relaxations around a vacancy and revealed that electronic excitations could make a contribution to the formation and migration entropies which was comparable to the vibrational contribution. The link between electronic structure and vacancy properties in body-centered cubic transition metals was analysed by using a simple tight-binding d-band model. The position of the Fermi level, with respect to the characteristic dip in the density of states, was shown to govern sharp variations in the vacancy parameters along the transition-metal series.

Impact of Electronic Structure Calculations on the Study of Diffusion in Metals. F.Willaime: Advances in Engineering Materials, 2001, 3[5], 283-9. See also: Materials Science and Technology, 2001, 17[7], 766-71