Growth Mechanism and Origin of High sp^{3} Content in Tetrahedral Amorphous Carbon.
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Publication Date
2018-04-20Journal Title
Physical Review Letters
ISSN
1079-7114
Publisher
American Physical Society
Volume
120
Issue
16
Number
166101
Language
eng
Type
Article
This Version
AM
Metadata
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Caro, M. A., Deringer, V., Koskinen, J., Laurila, T., & Csányi, G. (2018). Growth Mechanism and Origin of High sp^{3} Content in Tetrahedral Amorphous Carbon.. Physical Review Letters, 120 (16. 166101) https://doi.org/10.1103/PhysRevLett.120.166101
Abstract
We study the deposition of tetrahedral amorphous carbon (ta-C) films from molecular dynamics simulations based on a machine-learned interatomic potential trained from density-functional theory data. For the first time, the high sp^{3} fractions in excess of 85% observed experimentally are reproduced by means of computational simulation, and the deposition energy dependence of the film's characteristics is also accurately described. High confidence in the potential and direct access to the atomic interactions allow us to infer the microscopic growth mechanism in this material. While the widespread view is that ta-C grows by "subplantation," we show that the so-called "peening" model is actually the dominant mechanism responsible for the high sp^{3} content. We show that pressure waves lead to bond rearrangement away from the impact site of the incident ion, and high sp^{3} fractions arise from a delicate balance of transitions between three- and fourfold coordinated carbon atoms. These results open the door for a microscopic understanding of carbon nanostructure formation with an unprecedented level of predictive power.
Sponsorship
This research was financially supported by the Academy of Finland through Grants No. 310574 and No. 285526. Computational resources were provided by CSC—IT Center for Science, Finland, though Projects No. 2000634 and No. 2000300. V. L. D. gratefully acknowledges a fellowship from the Alexander von Humboldt Foundation, a Leverhulme Early Career Fellowship, and support from the Isaac Newton Trust.
Funder references
Isaac Newton Trust (1624(n))
Engineering and Physical Sciences Research Council (EP/P022596/1)
Isaac Newton Trust (17.08(c))
Leverhulme Trust (ECF-2017-278)
Identifiers
External DOI: https://doi.org/10.1103/PhysRevLett.120.166101
This record's URL: https://www.repository.cam.ac.uk/handle/1810/285723
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