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

摘要

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