Long-Range Interaction Between Adatoms in Graphene

TL;DR

This paper develops a theory for electron-mediated long-range interactions between adatoms in graphene, revealing a Casimir-like fermionic interaction that influences adatom aggregation behavior.

Contribution

It introduces a novel theoretical framework describing long-range adatom interactions in graphene mediated by electrons, especially for resonant scattering scenarios.

Findings

Long-range 1/r interaction in graphene adatoms.

Interaction can be attractive or repulsive based on sublattice positioning.

Adatom attraction leads to aggregation instability.

Abstract

We present a theory of electron-mediated interaction between adatoms in graphene. In the case of resonant scattering, relevant for hydrogentated graphene, a long-range 1/r interaction is found. This interaction can be viewed as a fermionic analog of the Casimir interaction, in which massless fermions play the role of photons. The interaction is an attraction or a repulsion depending on whether the adatoms reside on the same sublattice or on different sublattices, with attraction dominating for adatoms randomly spread over both sublattices. The attractive nature of these forces creates an instability under which adatoms tend to aggregate.