Article abstract
Nature Materials 2, 333 - 337 (2003)
Published online: 13 April 2003 | doi:10.1038/nmat876
Subject Categories: Mechanical properties | Materials for energy | Nanoscale materials | Computation, modelling and theory
Wigner defects bridge the graphite gap
Rob H. Telling1, Chris P. Ewels2, Ahlam A. El-Barbary1 & Malcolm I. Heggie1
Abstract
We present findings on the structure, energies and behaviour of defects in irradiated graphitic carbon materials. Defect production due to high-energy nuclear radiations experienced in graphite moderators is generally associated with undesirable changes in internal energy, microstructure and physical properties—the so-called Wigner effect. On the flip side, the controlled introduction and ability to handle such defects in the electron beam is considered a desirable way to engineer the properties of carbon nanostructures. In both cases, the atomic-level details of structure and interaction are only just beginning to be understood. Here, using a model system of crystalline graphite, we show from first-principles calculations, new details in the behaviour of vacancy and interstitial defects. We identify a prominent barrier-state to energy release, reveal a surprising ability of vacancy defects to bridge the widely spaced atomic layers, and discuss physical property and microstructure changes during irradiation, including interactions with dislocations.
- The University of Sussex, Falmer, Brighton BN1 9QJ, UK
- Present address: DMSC, ONERA, 29 Avenue de la Division Leclerc, 92322 Chatillon, France
Correspondence to: Rob H. Telling1 e-mail: r.h.telling@sussex.ac.uk
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