Tunable magnetoresistance in spin-orbit coupled graphene junctions

TL;DR

This paper investigates how Rashba spin-orbit interaction influences magnetoresistance and spin transport in graphene junctions, revealing tunable spin-polarized conductance, spin-valve effects, and noise oscillations, with implications for spintronics applications.

Contribution

It demonstrates the control of spin-polarized conductance and magnetoresistance in graphene junctions through RSOI strength, introducing a tunable spintronic device concept.

Findings

Rashba spin-orbit interaction can block Klein tunneling in graphene junctions.

Spin-polarized conductance depends on RSOI strength and magnetic exchange field.

The junction exhibits a spin-valve effect with large negative magnetoresistance.

Abstract

Using the Landauer-B\"utikker formalism, we study the graphene magneto-transport in the presence of Rashba spin-orbit interaction (RSOI). We show that the angle resolved transmission probability in the proposed structures can be tuned by the RSOI strength. The transmission spectrum show Klein tunneling in the parallel (P) magnetization configuration which can be blocked by the RSOI. This effect is also observable for the anti-parallel (AP) magnetization configuration in different incident angle. The numerical results shows that the spin-polarized conductance strongly depends on the strength of the RSOI and can be generated by tuning the magnetic exchange field and RSOI strength. This spin-polarized conductance is a sensitive oscillatory function of the thickness of the RSO region. Because of the spin-flip effect, the junction shows a spin-valve effect with large and negative magnetoresistance (MR) and spin-magnetoresistance (SMR) in the presence of RSOI. When the RSOI is on, the frequency and amplitude of shot-noise and Fano factor's oscillations are also increased. These results can provide a way to extending the application of graphene-based junctions in spintronics.