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Phys. Rev. Lett. 92, 175503 (2004) [4 pages]

Stability and Mobility of Mono- and Di-Interstitials in α-Fe

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Chu-Chun Fu and F. Willaime
Service de Recherches de Métallurgie Physique, CEA/Saclay, 91191 Gif-sur-Yvette Cedex, France

P. Ordejón
Institut de Ciència de Materials de Barcelona (CSIC), Campus de la U.A.B., 08193 Bellaterra, Spain

Received 12 January 2004; published 30 April 2004

We report a detailed ab initio study of the stability and migration of self-interstitial atoms (SIAs) and di-interstitials (di-SIAs) in α-Fe. The ⟨110⟩ dumbbell is confirmed to be the most stable SIA configuration, 0.7 eV below the ⟨111⟩ dumbbell. The lowest-energy migration path corresponds to a nearest-neighbor translation-rotation jump with a barrier of 0.34 eV. The most stable configuration for di-SIAs consists of ⟨110⟩ parallel dumbbells. Their migration mechanism is similar to that for SIAs, with an activation energy of 0.42 eV. These results are at variance with predictions from existing empirical potentials and allow one to reconcile theory with experiments.

© 2004 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevLett.92.175503
DOI:
10.1103/PhysRevLett.92.175503
PACS:
61.72.Ji, 31.15.Ar, 66.30.Lw, 67.80.Mg