First-principles modeling of the interactions of iron impurities with graphene and graphite

TL;DR

This study uses first-principles modeling to compare how iron impurities interact with graphene and graphite, revealing significant differences in their energetics and impurity behaviors.

Contribution

It provides new insights into the energetics and mobility of iron impurities in graphene and graphite, highlighting their different effects and stability.

Findings

Iron atoms prefer interlayer insertion in graphite over surface adsorption.

High mobility of iron adatoms on graphite surfaces is observed.

Iron impurities are more destructive in graphite than in graphene.

Abstract

Results of first principles modelling of interactions graphene and graphite with iron impurities predict the colossal difference between these two carbon allotropes. Insertion of the iron atoms between the planes of graphite is much more energetically favourable than adsorption of the iron adatom at graphite or graphene surface. High mobility of iron adatom over graphite surface and within bulk graphite is reported. Calculated values of formation energies for the substitutional iron impurities suggest that iron is more destructive for graphite than for graphene. This effect caused formation of uniform carbon environment of the iron atom inside the multilayer system. In contrast to graphene segregation of the substitutional iron impurities in graphite at the ambient conditions is not energetically favourable. Enhancement of interlayer bonding in contaminated graphite and purity of graphene from iron impurities are also reported.