Double-walled silicon nanotubes: an ab initio investigation

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Silicon nanotubes (SiNTs) have been synthesized with multi-walled structures featuring [Formula: see text] and [Formula: see text] hybridizations.
• Existing theoretical models often adapt carbon nanotube ([Formula: see text]) structures, which are energetically unfavorable for silicon due to its tendency for [Formula: see text] bonding.

Purpose of the Study:

• To investigate the structural and electronic properties of double-walled silicon nanotubes using ab initio simulations.
• To propose novel silicon nanotube structures that accommodate silicon's natural [Formula: see text] hybridization.

Main Methods:

• Ab initio simulations based on density functional theory (DFT).
• Investigation of double-walled silicon nanotube configurations.

Main Results:

• Identified layered silicon nanotube structures with predominantly [Formula: see text] hybridization and some [Formula: see text] atoms on the outer wall.
• Lowest-energy structures exhibit metallic electronic behavior.
• Demonstrated the possibility of inducing a metal-semiconductor transition by applying strain.

Conclusions:

• Silicon nanotubes possess distinct properties compared to carbon nanotubes, primarily due to lattice distortions favoring silicon's tetravalent bonding.
• The proposed [Formula: see text]-rich silicon nanotube structures are energetically favorable and exhibit tunable electronic properties.
• These findings offer new insights into the fundamental behavior of silicon-based nanostructures.