Validating molecular dynamics with direct imaging of radiation damage debris

P. D. Lane, G. J. Galloway, R. J. Cole, Marco Caffio, Renald Schaub, G. J. Ackland

Research output: Contribution to journalArticlepeer-review

11 Citations (Scopus)


We present a combined experimental and simulation approach to studying the primary damage caused by ion irradiation. We have examined a surface of copper subjected to 500 eV Ar+ ion bombardment using scanning tunnelling microscopy (STM) and observed craterlike regions of damage, with a central hole surrounded by adatoms. Molecular dynamics (MD) simulations reproduce this structure and enable us to study the formation process. We find both qualitative and quantitative agreement between the defect structures observed in STM
and MD, providing a rare direct validation of the MD simulation. We observe a process in which a stress wave produces defect clusters fully formed at the surface, in contrast to the conventional bulk picture of creation, migration, and aggregation of point defects. This produces a characteristic crater structure. We also observe one-dimensional stress propagation events, which produce defects far from the initial collision and cooling of the thermal spike without self diffusion.

Original languageEnglish
Article number094111
Pages (from-to)094111
Number of pages6
JournalPhysical Review. B, Condensed matter and materials physics
Issue number09
Publication statusPublished - 29 Mar 2012


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