Two B-C-O Compounds: Structural, Mechanical Anisotropy and Electronic Properties under Pressure

Area of Science:

• Materials Science
• Solid-State Physics
• Computational Chemistry

Background:

• Ternary light element compounds are crucial for advanced material applications.
• Understanding the properties of boron-carbon-oxygen systems is essential for discovering novel materials.

Purpose of the Study:

• To systematically investigate the structural, stability, mechanical, elastic anisotropy, and electronic properties of B₂CO₂ and B₆C₂O₅.
• To assess the potential of these compounds as superhard materials and wide-bandgap semiconductors.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Elastic constants and phonon dispersion calculations for stability analysis.
• Lyakhov-Oganov model for hardness prediction.

Main Results:

• Both B₂CO₂ and B₆C₂O₅ are mechanically and dynamically stable up to 20 GPa.
• B₂CO₂ and B₆C₂O₅ are wide-bandgap semiconductors with indirect energy gaps of 5.66 eV and 5.24 eV, respectively.
• B₂CO₂ is identified as a potential superhard material (hardness 41.7 GPa), while B₆C₂O₅ is softer (29.6 GPa) and more machinable.

Conclusions:

• B₂CO₂ and B₆C₂O₅ are stable ternary compounds with promising semiconductor properties.
• B₂CO₂'s superhard potential and B₆C₂O₅'s machinability offer distinct application possibilities.
• The elastic anisotropy differs between the two compounds, with B₆C₂O₅ showing greater shear modulus anisotropy and B₂CO₂ greater Young's modulus anisotropy.