Cp-Graphyne: A Low-Energy Graphyne Polymorph with Double Distorted Dirac Points.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Two-dimensional (2D) carbon allotropes, beyond graphene, are actively researched for novel electronic and mechanical properties.
• The graphyne family, a class of 2D carbon materials, offers diverse structural and electronic characteristics.

Purpose of the Study:

• To propose and investigate a new 2D carbon allotrope, cp-graphyne, using first-principle calculations.
• To evaluate the energetic favorability, stability, and electronic properties of the proposed cp-graphyne.

Main Methods:

• First-principle density functional theory (DFT)-based calculations were employed.
• Analysis included lattice dynamics, thermal and mechanical properties, and electronic band structure.

Main Results:

• Cp-graphyne was identified as an energetically favorable 2D carbon material, outperforming other graphyne semimetals.
• Excellent dynamic, thermal, and mechanical stabilities were demonstrated.
• A semimetallic nature with double distorted Dirac points and highly anisotropic Fermi velocities (1.50–8.20 × 10^5 m/s) was observed.
• Cp-graphyne bilayers exhibit self-doped Dirac-like points near the Fermi level.

Conclusions:

• Cp-graphyne represents a stable and energetically preferred 2D carbon allotrope with unique electronic properties.
• The anisotropic electronic behavior and Dirac points suggest potential applications in advanced electronic devices.
• Further investigation into bilayer cp-graphyne reveals tunable electronic characteristics.