Imprinting Tunable ${\pi}$-Magnetism in Graphene Nanoribbons via Edge Extensions

TL;DR

This study theoretically demonstrates how asymmetric edge extensions with naphtho groups in graphene nanoribbons can induce and tune ${ m f extpi}$-magnetism, enabling control over magnetic states for spintronics applications.

Contribution

We show that edge extensions act as spin-$rac{1}{2}$ centers and their arrangement controls magnetic interactions, revealing tunable ${ m f extpi}$-magnetism in graphene nanoribbons.

Findings

Edge extensions induce localized spin-$rac{1}{2}$ centers.

Magnetic coupling depends on the position of naphtho groups.

External stimuli can switch magnetic phases.

Abstract

Magnetic carbon nanostructures are currently under scrutiny for a wide spectrum of applications. Here, we theoretically investigate armchair graphene nanoribbons patterned with asymmetric edge extensions consisting of laterally fused naphtho groups, as recently fabricated via on-surface synthesis. We show that an individual edge extension acts as a spin-$\frac{1}{2}$ center and develops a sizable spin-polarization of the conductance around the band edges. The Heisenberg exchange coupling between a pair of edge extensions is dictated by the position of the second naphtho group in the carbon backbone, thus enabling ferromagnetic, antiferromagnetic, or non-magnetic states. The periodic arrangement of edge extensions yields full spin-polarization at the band extrema, and the accompanying ferromagnetic ground state can be driven into non-magnetic or antiferromagnetic phases through external stimuli. Overall, our work reveals precise tunability of the ${\pi}$-magnetism in graphene nanoribbons induced by naphtho groups, thereby establishing these one-dimensional architectures as suitable platforms for logic spintronics.