Phase separation of hydrogen atoms adsorbed on graphene and the smoothness of the graphene-graphane interface

TL;DR

This study models hydrogen atom adsorption on graphene, revealing phase separation into graphane and graphene with a smooth interface, which could benefit device fabrication.

Contribution

It introduces a modified Falicov-Kimball model to analyze phase separation and interface properties in hydrogenated graphene systems.

Findings

System separates into hydrogenated and non-hydrogenated phases.

Graphene-graphane interface is straight and slightly rippled.

Smooth interface could aid in fabricating graphene-based devices.

Abstract

The electronic properties of a graphene sheet with attached hydrogen atoms is studied using a modified Falicov-Kimball model on the honeycomb lattice. It is shown that in the ground state this system separates into two phases: fully hydrogenated graphene (graphane) and hydrogen-free graphene. The graphene-graphane boundary acquires a positive interface tension. Therefore, the graphene-graphane interface becomes a straight line, slightly rippled by thermal fluctuations. A smooth interface may be useful for the fabrication of mesoscopic graphene-based devices.