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 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 content. We show that pressure waves lead to bond rearrangement away from the impact site of the incident ion, and high 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.
- Received 29 December 2017
DOI:https://doi.org/10.1103/PhysRevLett.120.166101
© 2018 American Physical Society
Physics Subject Headings (PhySH)
Synopsis
How Diamond-Like Carbon Films Grow
Published 18 April 2018
Machine-learning-based molecular dynamics simulations explain the growth mechanism of diamond-like amorphous carbon films.
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