ReaxFF Parameter Set for Boron Clusters and Icosahedral Boron Crystals: Comparison with Density Functional Theory and...

Area of Science:

• Materials Science
• Computational Chemistry
• Condensed Matter Physics

Background:

• Icosahedral boron materials show promise for applications in superhard materials, semiconductors, and energy storage.
• Synthesizing high-quality icosahedral boron crystals remains a significant challenge hindering technological development.
• Accurate computational models are needed to predict synthesis conditions for these advanced materials.

Purpose of the Study:

• To develop and refine ReaxFF parameters for simulating the nucleation and growth of icosahedral boron crystals.
• To improve the computational prediction of synthesis conditions for high-quality icosahedral boron.

Main Methods:

• Tested and refined ReaxFF parameters by matching relative energies of small boron clusters to Density Functional Theory (DFT) calculations.
• Utilized a training set of B₈₀ clusters, including core-shell and single-shell structures.
• Validated the refined parameters against DFT for a test set of 58 boron clusters (8-103 atoms) and compared with existing potentials.

Main Results:

• The refined ReaxFF parameter set accurately ranked B₈₀ clusters, outperforming most existing parameters and some machine-learning potentials.
• Achieved improved agreement with DFT for boron clusters ranging from 8 to 103 atoms.
• Simulations showed enhanced local icosahedral structure in crystallization and yielded a boron solubility in molten nickel consistent with experimental data.

Conclusions:

• The refined ReaxFF parameters provide a more accurate computational tool for studying icosahedral boron crystal formation.
• This advancement facilitates the prediction of synthesis conditions, paving the way for practical applications of these materials.
• The improved model offers better insights into boron cluster energies, crystallization processes, and solubility.