Intrinsic Half-Metallicity in Modified Graphene Nanoribbons

TL;DR

This study uses first-principles calculations to show that doping graphene nanoribbons with boron and nitrogen can induce stable anti-ferromagnetic states and half-metallicity, promising for spintronics applications.

Contribution

It demonstrates that doping and dopant positioning can induce half-metallicity in graphene nanoribbons regardless of width or electric field influence.

Findings

Doped nanoribbons stabilize in anti-ferromagnetic states.

Half-metallicity occurs in ZBNNRs with polyacene units.

Electronic properties are tunable by doping and electric fields.

Abstract

We perform first-principles calculations based on density functional theory to study quasi one-dimensional edge-passivated (with hydrogen) zigzag graphene nanoribbons (ZGNRs) of various widths with chemical dopants, boron and nitrogen, keeping the whole system isoelectronic. Gradual increase in doping concentration takes the system finally to zigzag boron nitride nanoribbons (ZBNNRs). Our study reveals that, for all doping concentrations the systems stabilize in anti-ferromagnetic ground states. Doping concentrations and dopant positions regulate the electronic structure of the nanoribbons, exhibiting both semiconducting and half-metallic behaviors as a response to the external electric field. Interestingly, our results show that ZBNNRs with terminating polyacene unit exhibit half-metallicity irrespective of the ribbon width as well as applied electric field, opening a huge possibility in spintronics device applications.