Novel superhard semiconducting structures of C₈B₂N₂ predicted using the first-principles approach

Area of Science:

• Materials Science
• Computational Chemistry
• Solid-State Physics

Background:

• Boron carbon nitride (BCN) phases are explored for their potential superhard and semiconducting properties.
• The P3m1 phase of BCN is known for exceptional mechanical characteristics.
• Existing BCN structures like t-C8B2N2 serve as a basis for exploring new material designs.

Purpose of the Study:

• To predict and characterize novel superhard semiconducting structures of C8B2N2.
• To investigate the mechanical and electronic properties of these new structures under high pressure.
• To compare the predicted materials with existing superhard semiconductors like cubic boron nitride (c-BN).

Main Methods:

• First-principles calculations were employed to predict new C8B2N2 crystal structures.
• Mechanical and dynamical stability analyses were performed up to 100 GPa.
• Electronic band structures and electron localization functions were calculated to understand electronic properties.

Main Results:

• Three novel C8B2N2 structures in the P3m1 space group were successfully predicted.
• These structures exhibit superior energetic stability compared to previously reported t-C8B2N2.
• Calculated hardness values range from 82.0 to 83.1 GPa, exceeding that of t-C8B2N2 and c-BN.
• Indirect bandgaps of 4.164, 4.692, and 3.582 eV were determined for the new structures.
• Stronger carbon-carbon covalent bonds contribute to the enhanced hardness.

Conclusions:

• The predicted C8B2N2 structures represent promising candidates for next-generation superhard semiconductors.
• These materials demonstrate potential to outperform conventional superhard materials in both hardness and semiconducting applications.
• Further experimental synthesis and characterization are warranted to validate these computational findings.