Persistent currents in carbon nanotubes

TL;DR

This paper explores how doping-induced shifts in Fermi energy affect persistent currents in carbon nanotubes, revealing significant changes in electronic behavior based on nanotube structure and doping levels.

Contribution

It provides a detailed analysis of the impact of Fermi energy shifts on persistent currents in zigzag and armchair nanotubes, considering experimental doping levels.

Findings

Fermi energy shifts dramatically alter persistent currents.

Electronic structure varies with nanotube type and doping.

Persistent currents depend on Fermi surface shape changes.

Abstract

Persistent currents driven by a static magnetic flux parallel to the carbon nanotube axis are investigated. Owing to the hexagonal symmetry of graphene the Fermi contour expected for a 2D-lattice reduces to two points. However the electron or hole doping shifts the Fermi energy upwards or downwards and as a result, the shape of the Fermi surface changes. Such a hole doping leading to the Fermi level shift of (more or less) 1eV has been recently observed experimentally. In this paper we show that the shift of the Fermi energy changes dramatically the persistent currents and discuss the electronic structure and possible currents for zigzag as well as armchair nanotubes.