Functionalization of edge reconstructed graphene nanoribbons by H and Fe: A density functional study

TL;DR

This study uses density functional theory to analyze how hydrogen and iron atoms attach to edge-reconstructed graphene nanoribbons, revealing stability, phonon behavior, and magnetic properties relevant for nanoelectronic applications.

Contribution

It provides new insights into the stability, phonon modes, and magnetic interactions of functionalized edge-reconstructed graphene nanoribbons using ab initio calculations.

Findings

Hydrogenation is more favorable at reconstructed edges than unreconstructed edges.

Edge reconstruction affects phonon modes, leading to hardened optical phonons.

Fe functionalization results in dimerized chains and variable magnetic coupling.

Abstract

In this paper, we have studied functionalization of 5-7 edge-reconstructed graphene nanoribbons by ab initio density functional calculations. Our studies show that hydrogenation at the reconstructed edges is favorable in contrast to the case of unreconstructed 6-6 zigzag edges, in agreement with previous theoretical results. Thermodynamical calculations reveal the relative stability of single and dihydrogenated edges under different temperatures and chemical potential of hydrogen gas. From phonon calculations, we find that the lowest optical phonon modes are hardened due to 5-7 edge reconstruction compared to the 6-6 unreconstructed hydrogenated edges. Finally, edge functionalization by Fe atoms reveals a dimerized Fe chain structure along the edges. The magnetic exchange coupling across the edges varies between ferromagnetic and antiferromagnetic ones with the variation of the width of the nanoribbons.