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Ab initio structural dynamics of pure and nitrogen-containing amorphous carbon
Brad A Steele1, Sorin Bastea2, I-Feng W Kuo1
1Lawrence Livermore National Laboratory, Physical and Life Sciences Directorate, 7000 East Ave., Livermore, California, 94550, USA.
Scientific Reports
|November 11, 2023
Summary
Amorphous carbon
Area of Science:
- Materials Science
- Computational Chemistry
- Condensed Matter Physics
Background:
- Amorphous carbon (a-C) properties depend on structure, density, and impurities.
- Understanding a-C formation is crucial for tailoring its applications.
Purpose of the Study:
- Investigate the evolution of amorphous carbon structure under high temperature and pressure.
- Analyze the impact of nitrogen incorporation on a-C properties.
Main Methods:
- Utilized ab initio molecular dynamics simulations.
- Simulated liquid quenching process at high temperatures and pressures.
- Examined structural evolution on sub-nanosecond timescales.
Main Results:
- Graphite-like densities promote layered sp2 structures (similar to MAC).
- Diamond-like densities result in tetrahedral sp3 structures (DLC).
- Nitrogen addition reinforces carbon structural motifs and inhibits phase separation.
Conclusions:
- a-C structure is highly sensitive to density and processing conditions.
- Nitrogen impurities remain embedded in a-C at high pressures.
- Simulations provide insights into a-C and a-CN formation mechanisms.
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