Persistent currents in a carbon nanotube torus encapsulated with a carbon ring

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Mesoscopic rings are crucial for studying quantum phenomena.
• Persistent current in such systems is sensitive to electronic interactions.
• Toroidal carbon nanostructures offer unique geometries for investigation.

Purpose of the Study:

• To model a toroidal carbon nanowire (TCNW) for studying persistent current.
• To investigate the electronic structure and persistent current (I(pc)) in TCNWs.
• To understand the influence of tube-ring interactions on I(pc).

Main Methods:

• Utilized a toroidal carbon nanotube (TCN) and encapsulated carbon ring model.
• Employed the tight-binding formalism to analyze electronic structure.
• Investigated charge transfer, Fermi level shifts, and band overlaps under magnetic flux.

Main Results:

• Tube-ring interactions cause charge transfer from the inner ring to the outer TCN.
• Fermi level rises and band overlaps occur within specific flux ranges.
• In metallic TCNWs, I(pc) is dominated by the TCNW; in semiconducting TCNWs, I(pc) mirrors the inner ring.

Conclusions:

• Persistent current in mesoscopic rings is highly dependent on the surrounding matrix.
• Semiconducting or insulating environments are proposed for optimal measurement of I(pc).
• TCNW model provides insights into quantum transport in nanostructured materials.