Localized edge vibrations and edge reconstruction by Joule heating in graphene nanostructures

TL;DR

This paper presents a microscopic theory explaining how Joule heating induces edge reconstruction in graphene nanostructures, highlighting localized vibrations at edge interfaces as the key mechanism.

Contribution

It introduces a density functional theory-based model linking current-induced vibrations to edge reconstruction in graphene.

Findings

Localized vibrations occur at unpassivated armchair edges.

Joule heating excites these vibrations, leading to edge reconstruction.

The theory aligns with experimental observations of edge smoothing.

Abstract

Control of the edge topology of graphene nanostructures is critical to graphene-based electronics. A means of producing atomically smooth zigzag edges using electronic current has recently been demonstrated in experiments [Jia et al., Science 323, 1701 (2009)]. We develop a microscopic theory for current-induced edge reconstruction using density functional theory. Our calculations provide evidence for localized vibrations at edge-interfaces involving unpassivated armchair edges. We demonstrate that these vibrations couple to the current, estimate their excitation by Joule heating, and argue that they are the likely cause of the reconstructions observed in the experiments.