Spin Valve Effect in ZigZag Graphene Nanoribbons by Defect Engineering

TL;DR

This paper demonstrates how defect engineering at the edges of zigzag graphene nanoribbons can induce a spin valve effect, enabling potential applications in spintronic switches and field-effect devices.

Contribution

It introduces a theoretical model showing how edge defects and gating can control spin-dependent electronic properties in graphene nanoribbons.

Findings

Gate induces semiconductor-metal transition in clean ribbons.

Edge defects close the spin-split bandgap under gating.

Potential for designing spintronic switches and devices.

Abstract

We report on the possibility for a spin valve effect driven by edge defect engineering of zigzag graphene nanoribbons. Based on a mean-field spin unrestricted Hubbard model, electronic band structures and conductance profiles are derived, using a self-consistent scheme to include gate-induced charge density. The use of an external gate is found to trigger a semiconductor-metal transition in clean zigzag graphene nanoribbons, whereas it yields a closure of the spin-split bandgap in the presence of Klein edge defects. These features could be exploited to make novel charge and spin based switches and field effect devices.