Molecular dynamics simulation of ion focusing and crowdion formation in self-ion-irradiated Fe

D Chen and L Shao, NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS, 272, 33-36 (2012).

DOI: 10.1016/j.nimb.2011.01.027

We have used molecular dynamics (MD) simulation to investigate damage and defect development in a < 1 0 0 > Fe substrate upon 2 keV Fe ion bombardment. The damage cascade formation is accompanied by atomic shifting over a limited distance along the direction of one atomic row, which leads to formation of crowdions aligned with < 1 1 1 > direction. At the end of structural relaxation and defect recombination, crowdions lead to formation of dumbbell defects - a type of vacancy-interstitial complexes having one vacancy between a pair of slightly displaced interstitials. The dumbbell defects are initially oriented along < 1 1 1 > direction. After a typical period of 0.2 ps, some dumbbell defects rotate towards < 1 1 0 > direction. Crowdion and dumbbell defect formation influence the time dependent damage buildups. (C) 2011 Elsevier B.V. All rights reserved.

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