Atomic and electronic structure of graphene/Sn-Ni(111) and graphene/Sn-Cu(111) surface alloy interfaces

Abstract

First-principles density functional theory calculations were performed to investigate the effect of Sn surface alloying on the strength of interface interactions between graphene and Ni(111) or Cu(111) substrates. A substantial reduction of graphene-metal interactions was observed for the graphene/Sn-Ni(111) interface: binding energy was reduced from 0.055 eV/(C atom) to 0.015 eV/(C atom); interface distance was increased from 2.12 Å to 3.52 Å. The initially weak graphene/Cu(111) interface was hardly affected by Sn surface alloying. Electronic structure calculations, including local density of states and simulated scanning tunneling microscopy images, provide further details on the changing character of graphene-Ni(111) interactions upon Sn alloying.