Shot Noise Probing of Magnetic Ordering in Zigzag Graphene Nanoribbons

TL;DR

This paper shows that shot noise measurements can be used as a sensitive, all-electrical method to detect magnetic ordering along the edges of zigzag graphene nanoribbons, revealing edge-localized ferromagnetism.

Contribution

It introduces the concept that shot noise in ZGNRs is significantly affected by edge-induced magnetic states, providing a novel probe for low-dimensional magnetism.

Findings

Shot noise is enhanced by edge magnetic ordering.

Spin-polarized currents show greater shot noise sensitivity.

Edge topology influences shot noise behavior.

Abstract

The nonequilibrium time-dependent fluctuations of charge current have recently emerged as a sensitive experimental tool to probe ballistic transport through evanescent wave functions introduced into clean wide and short graphene strips by the attached metallic electrodes. We demonstrate that such "pseudo-diffusive" shot noise can be substantially modified in zigzag graphene nanoribbon (ZGNR) due to the topology of its edges responsible for localized states that facilitate ferromagnetic ordering along the edge when Coulomb interaction is taken into account. Thus, the shot noise enhancement of unpolarized, and even more sensitively of spin-polarized, charge currents injected into ZGNR will act as an all-electrical and edge-sensitive probe of such low-dimensional magnetism.