Current-induced one-dimensional diffusion of Co ad-atoms on graphene nanoribbons

TL;DR

This study demonstrates current-induced one-dimensional diffusion of cobalt ad-atoms on graphene nanoribbons, revealing thermally activated atomic motion and potential for single-atom electromigration research.

Contribution

It provides experimental evidence of current-driven atomic diffusion on graphene nanoribbons using STM, highlighting thermally activated motion at elevated temperatures.

Findings

Co ad-atoms move along nanoribbons under current

Diffusion follows a thermally activated random walk model

Nanoribbons reach temperatures above 100 K during experiments

Abstract

One-dimensional diffusion of Co ad-atoms on graphene nanoribbons has been induced and investigated by means of scanning tunnelling microscopy (STM). To this end, the nanoribbons and the Co ad-atoms have been imaged before and after injecting current pulses into the nanoribbons, with the STM tip in direct contact with the ribbon. We observe current-induced motion of the Co atoms along the nanoribbons, which is approximately described by a distribution expected for a thermally activated one-dimensional random walk. This indicates that the nanoribbons reach temperatures far beyond 100 K, which is well above the temperature of the underlying Au substrate. This model system can be developed further for the study of electromigration at the single-atom level.