Spin configurations of carbon nanotube in a nonuniform external potential

TL;DR

This paper theoretically investigates how nonuniform external potentials influence the ground state spin configurations of finite-length armchair carbon nanotubes, revealing potential for controlled spin flips relevant to quantum applications.

Contribution

It introduces a model showing that local external potentials can induce spin flips in nanotubes by altering the electron spectrum and Coulomb interactions.

Findings

External potential variation causes spin flips in nanotube ground states.

The model explains dependence of Coulomb blockade peaks on magnetic fields.

Potential applications in spintronics and quantum information processing.

Abstract

We study, theoretically, the ground state spin of a carbon nanotube in the presence of an external potential. We find that when the external potential is applied to a part of the nanotube, its variation changes the single electron spectrum significantly. This, in combination with Coulomb repulsion and the symmetry properties of a finite length armchair nanotube induces spin flips in the ground state when the external potential is varied. We discuss the possible application of our theory to recent measurements of Coulomb blocked peaks and their dependence on a weak magnetic field in armchair carbon nanotubes.