Toward Planar Iodine 2D Crystal Materials.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• The octet rule governs hybridization in many 2D materials, but struggles with elements in groups VIA-VIIA due to abundant outer electrons.
• Existing models do not fully explain bonding and electronic properties for heavier p-block elements in 2D structures.

Purpose of the Study:

• To introduce a novel spd² hybridization rule applicable to halogen elements in 2D materials.
• To investigate the structural and electronic properties of a 2D iodine atomic layer (iodiene).
• To explore the potential for creating topological electronic phases in iodiene.

Main Methods:

• Theoretical modeling of electronic structure and bonding using spd² hybridization.
• Simulations of mechanical strain effects on the iodiene atomic layer.
• Analysis of band structure evolution under compression.

Main Results:

• A new spd² hybridization rule successfully accommodates all outer electrons of halogens.
• Stable iodiene sheets are formed via robust σ bonds.
• Application of compression strain induces π bond formation and band inversion.
• The transformation into a Dirac semimetal with Dirac points (arc or hoop) is observed.

Conclusions:

• The spd² hybridization rule provides a framework for understanding 2D materials involving halogen elements.
• Iodiene sheets exhibit tunable electronic properties, transitioning to a Dirac semimetal phase under strain.
• This work opens avenues for exploring novel topological materials based on p-block elements.