Amorphous silicene-a view from molecular dynamics simulation.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Chemistry

Background:

• Silicene, a 2D allotrope of silicon, has garnered interest for its unique electronic properties.
• Understanding the amorphous phase of silicene is crucial for exploring its potential applications.

Purpose of the Study:

• To simulate and characterize amorphous silicene (a-silicene) using molecular dynamics.
• To investigate the structural, thermodynamic, and potential electronic properties of a-silicene.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model a-silicene.
• Cooling from the melt was used to obtain amorphous structures of approximately 10^4 atoms.
• Analysis included total energy, radial distribution function (RDF), coordination number, ring/bond-angle distributions, and buckling distribution.

Main Results:

• Amorphous silicene was successfully formed, confirmed by diffraction patterns indicating a glass state.
• The glass transition temperature was estimated to be comparable to 3D silicon.
• a-Silicene exhibits a high concentration of defects, including adatoms, small/large rings, and linear defects, not present in crystalline silicene (c-silicene).
• Buckling is non-uniform across atoms, leading to a distorted structure compared to c-silicene.

Conclusions:

• The simulated a-silicene possesses a unique, defect-rich structure distinct from c-silicene.
• The distorted structure of a-silicene may lead to altered physico-chemical properties, including a potential band gap opening.
• The study provides insights into the formation and characteristics of amorphous 2D silicon under confinement.