Magnetic edge states in Aharonov-Bohm graphene quantum rings

TL;DR

This paper investigates how electron-electron interactions influence the electronic and magnetic properties of Aharonov-Bohm graphene quantum rings with various geometries, revealing geometry-dependent spin polarization effects.

Contribution

It provides a theoretical analysis of magnetic edge states in AB graphene quantum rings considering electron interactions and different geometries, highlighting spin polarization phenomena.

Findings

AB oscillations are affected by electron interactions.

Spin splitting depends on ring geometry and size.

Triangular rings exhibit spin-polarized AB oscillations.

Abstract

The effect of electron-electron interaction on the electronic structure of Aharonov-Bohm (AB) graphene quantum rings (GQRs) is explored theoretically using the single-band tight-binding Hamiltonian and the mean-field Hubbard model. The electronic states and magnetic properties of hexagonal, triangular and circular GQRs with different sizes and zigzag edge terminations are studied. The results show that, although the AB oscillations in the all types of nanoring are affected by the interaction, the spin splitting in the AB oscillations strongly depends on the geometry and the size of graphene nanorings. We found that the total spin of hexagonal and circular rings is zero and therefore, no spin splitting can be observed in the AB oscillations. However, the non-zero magnetization of the triangular rings breaks the degeneracy between spin-up and spin-down electrons, which produces spin-polarized AB oscillations.