Aharonov-Bohm effect and giant magnetoresistance in graphene nanoribbon rings

TL;DR

This paper demonstrates that graphene nanoribbon rings exhibit strong Aharonov-Bohm oscillations and giant magnetoresistance at room temperature, with potential applications in graphene-based magnetic sensors.

Contribution

The study provides a numerical analysis showing how magnetic fields can modulate electron transport in GNR rings, revealing conditions for giant magnetoresistance at room temperature.

Findings

Magnetoresistance reaches thousands percent in perfect GNR rings.

Strong AB oscillations observed at room temperature.

Edge disorder reduces but still maintains significant magnetoresistance.

Abstract

We report a numerical study on Aharonov-Bohm (AB) effect and giant magnetoresistance in rectangular rings made of graphene nanoribbons (GNRs). We show that in low energy regime where only the first subband of contact GNRs contributes to the transport, the transmission probability can be strongly modulated, i.e., almost fully suppressed, when tuning a perpendicular magnetic field. On this basis, strong AB oscillations with giant negative magnetoresistance can be achieved at room temperature. The magnetoresistance reaches thousands % in perfect GNR rings and a few hundred % with edge disordered GNRs. The design rules to observe such strong effects are also discussed. Our study hence provides guidelines for further investigations of the AB interference and to obtain high magnetoresistance in graphene devices.