An extensive ab initio study was made of self-interstitials. Contrary to the widely accepted picture, the <111> dumb-bell was found to be the most stable structure. The activated state for migration was the crowdion configuration, with an extremely low barrier (~0.01eV); suggesting the occurrence of 1-dimensional diffusion at low temperatures and of 3-dimensional diffusion at high temperatures. The predicted migration energies and self-interstitial structures were consistent with experiment.

Self-Interstitials in V and Mo. S.Han, L.A.Zepeda-Ruiz, G.J.Ackland, R.Car, D.J.Srolovitz: Physical Review B, 2002, 66[22], 220101