Anisotropic super-spin at the end of a carbon nanotube

TL;DR

This paper investigates the magnetic properties at the ends of carbon nanotubes, revealing an anisotropic super-spin influenced by enhanced spin-orbit coupling and Coulomb interactions, with potential for tunable anisotropy.

Contribution

It demonstrates the emergence of a super-spin with XY anisotropy at nanotube ends due to interaction effects and enhanced spin-orbit coupling, and shows how to amplify this anisotropy.

Findings

Super-spin at nanotube ends exhibits XY anisotropy around 10 mK.

Spin-orbit coupling is significantly stronger in nanotubes than in graphene.

Anisotropy can be increased by over an order of magnitude through partial super-spin suppression.

Abstract

Interaction-induced magnetism at the ends of carbon nanotubes is studied theoretically, with a special focus on magnetic anisotropies. Spin-orbit coupling, generally weak in ordinary graphene, is strongly enhanced in nanotubes. In combination with Coulomb interactions, this enhanced spin-orbit coupling gives rise to a super-spin at the ends of carbon nanotubes with an XY anisotropy on the order of 10 mK. Furthermore, it is shown that this anisotropy can be enhanced by more than one order of magnitude via a partial suppression of the super-spin.