Electronic and magnetic properties of superlattices of graphene/graphane nanoribbons with different edge hydrogenation

TL;DR

This study uses ab initio calculations to explore how hydrogenation at edges influences the electronic and magnetic properties of graphene/graphane nanoribbon superlattices, revealing tunable magnetic states and potential spintronics applications.

Contribution

It demonstrates how varying edge hydrogenation in graphene/graphane superlattices controls magnetic states, providing insights for designing graphene-based spintronic devices.

Findings

Fully hydrogenated interfaces lead to antiferromagnetic, semiconducting behavior.

Half hydrogenation induces ferromagnetism and near half-metallicity.

All configurations studied are semiconducting regardless of hydrogenation degree.

Abstract

Zigzag graphene nanoribbons patterned on graphane are studied using spin-polarized ab initio calculations. We found that the electronic and magnetic properties of the graphene/graphane superlattice strongly depends on the degree of hydrogenation at the interfaces between the two materials. When both zigzag interfaces are fully hydrogenated, the superlattice behaves like a freestanding zigzag graphene nanoribbon, and the magnetic ground state is antiferromagnetic. When one of the interfaces is half hydrogenated, the magnetic ground state becomes ferromagnetic, and the system is very close to being a half metal with possible spintronics applications whereas the magnetic ground state of the superlattice with both interfaces half hydrogenated is again antiferromagnetic. In this last case, both edges of the graphane nanoribbon also contribute to the total magnetization of the system. All the spin-polarized ground states are semiconducting, independent of the degree of hydrogenation of the interfaces. The ab initio results are supplemented by a simple tight-binding analysis that captures the main qualitative features. Our ab initio results show that patterned hydrogenation of graphene is a promising way to obtain stable graphene nanoribbons with interesting technological applications.