Stacking stability of C₂N bilayer nanosheet

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Monolayer C2N, a 2D graphene-like material, has been synthesized.
• Bilayer C2N can adopt various stacking configurations, including AA, AB, and AB'-stacking.

Purpose of the Study:

• Investigate the stability and electronic properties of different bilayer C2N stacking configurations.
• Determine the most stable stacking arrangement and its associated electronic band structure.
• Explore the energy landscape and interlayer sliding barriers in bilayer C2N.

Main Methods:

• First-principles calculations were employed to study bilayer C2N.
• Stability analysis of AA, AB, and AB'-stacking configurations was performed.
• Electronic band structures were calculated for different stacking arrangements.

Main Results:

• AB-stacking was initially identified as the most favorable configuration with the largest band gap.
• Energy landscape analysis revealed that the most stable positions are shifted from high-symmetry AB-stacking.
• Electronic band characteristics are tunable based on the stacking layer shift.
• The interlayer shear mode frequency was determined to be approximately 2.02 × 10^12 rad/s near local minima.

Conclusions:

• The most stable bilayer C2N structure deviates from high-symmetry configurations.
• Stacking configuration significantly impacts the electronic properties of bilayer C2N.
• Understanding these stacking-dependent properties is crucial for potential applications of C2N-based materials.