Spin signatures in the electrical response of graphene nanogaps

TL;DR

This paper investigates the electrical responses of graphene nanogaps to identify signatures of spin-polarized edge states, revealing that certain geometries exhibit low-voltage conductance features due to spin polarization.

Contribution

It demonstrates that nanogaps with wedge-shaped electrodes can host spin-polarized states, producing measurable electrical signatures, unlike perfectly zigzag-edged nanogaps.

Findings

Perfectly zigzag-edged nanogaps show no spin signatures.

Wedge-shaped electrodes host spin-polarized low-energy states.

Spin-polarized currents cause distinctive conductance features.

Abstract

We analyse the electrical response of narrow graphene nanogaps in search for transport signatures stemming from spin-polarized edge states. We find that the electrical transport across graphene nanogaps having perfectly defined zigzag edges does not carry any spin-related signature. We also analyse the magnetic and electrical properties of nanogaps whose electrodes have wedges that possibly occur in the currently fabricated nanogaps. These wedges can host spin polarized wedge low-energy states due to the bipartite nature of the graphene lattice. We find that these spin-polarized low-energy modes give rise to low-voltage signatures in the differential conductance and to distinctive features in the stability diagrams. These are caused by fully spin-polarized currents.