Tuning Spin Transport in a Graphene Antiferromagnetic Insulator

TL;DR

This paper demonstrates the first gate-controlled, selective tuning of long-distance spin transport through graphene-based antiferromagnetic insulators using quantum Hall edge states, advancing spintronics technology.

Contribution

It introduces a novel method to electrically tune spin transport in graphene AFMIs via quantum Hall edge states, enabling new control in antiferromagnetic spintronics.

Findings

Spin transport can be selectively tuned by modulating bias polarities and magnetic fields.

Reversing edge channel directions suppresses non-local spin signals.

The results establish methods for controlling pure spin transport in antiferromagnetic media.

Abstract

Long-distance spin transport through anti-ferromagnetic insulators (AFMIs) is a long-standing goal of spintronics research. Unlike conventional spintronics systems, monolayer graphene in quantum Hall regime (QH) offers an unprecedented tuneability of spin-polarization and charge carrier density in QH edge states. Here, using gate-controlled QH edges as spin-dependent injectors and detectors in an all-graphene electrical circuit, for the first time we demonstrate a selective tuning of ambipolar spin transport through graphene $\nu$=0 AFMIs. By modulating polarities of the excitation bias, magnetic fields, and charge carriers that host opposite chiralities, we show that the difference between spin chemical potentials of adjacent edge channels in the spin-injector region is crucial in tuning spin-transport observed across graphene AFMI. We demonstrate that non-local response vanishes upon reversing directions of the co-propagating edge channels when the spin-filters in our devices are no longer selective for a particular spin-polarization. Our results establish a versatile set of methods to tune pure spin transport via an anti-ferromagnetic media and open a pathway to explore their applications for a broad field of antiferromagnetic spintronics research.