Suppression of diffusion of hydrogen adatoms on graphene by effective adatom interaction

TL;DR

This paper investigates how effective interactions mediated by conduction electrons influence hydrogen adatom diffusion on graphene, finding that such diffusion is significantly slowed due to energy barriers caused by these interactions.

Contribution

It introduces a model for adatom interactions on graphene and estimates the slow diffusion rate of hydrogen adatoms considering inelastic mechanisms.

Findings

Hydrogen adatom diffusion is approximately one hop per millisecond.

Effective interactions create energy barriers affecting adatom mobility.

Diffusion is slowed by inelastic mechanisms like phonon and electron coupling.

Abstract

Resonant graphene dopants, such as hydrogen adatoms, experience long-range effective interaction mediated by conduction electrons. As a result of this interaction, when several adatoms are present in the sample, hopping of adatoms between sites belonging to different sublattices involves significant energy changes. Different inelastic mechanisms facilitating such hopping -- coupling to phonons and conduction electrons -- are considered. It is estimated that the diffusion of hydrogen adatoms is rather slow, amounting to roughly one hop to a nearest neighbor per millisecond.