An ab initio first-principles study of defect-induced self-diffusion in sodium was illustrated. Calculations of the migration energy and of the phonon spectrum in the presence of a vacancy confirmed hypotheses on low barriers and high migration entropies. Results on the relative contributions of various defect mechanisms to the sodium self-diffusion coefficient, obtained via direct simulation, indicated that the interstitial was a significant contributor to self-diffusion at temperatures close to melting, thus providing a possible explanation for the bending of the Arrhenius plot at high temperatures.

Self-Diffusion in Sodium via ab initio Molecular Dynamics. Smargiassi, E.: Physical Review B, 2002, 65[1], 012301