Graphene nanoring as a tunable source of polarized electrons

TL;DR

This paper introduces a graphene nanoring device that acts as a tunable spin filter, enabling control over electron spin polarization via a side-gate voltage, with potential applications in spintronics.

Contribution

The study presents a novel graphene-based spin filter device that allows electrical tuning of spin-polarized current using a ferromagnetic nanoring structure.

Findings

Current and polarization are controllable by side-gate voltage.

The device can serve as a tunable source of polarized electrons.

Spin polarization is achieved through exchange interaction with the ferromagnetic strip.

Abstract

We propose a novel spin filter based on a graphene nanoring fabricated above a ferromagnetic strip. The exchange interaction between the magnetic moments of the ions in the ferromagnet and the electron spin splits the electronic states, and gives rise to spin polarization of the conductance and the total electric current. We demonstrate that both the current and its polarization can be controlled by a side-gate voltage. This opens the possibility to use the proposed device as a tunable source of polarized electrons.