  The effect of Mn intercalation on the atomic, electronic and magnetic
structure of the graphene/Cu(111) interface is studied using state-of-the-art
density functional theory calculations. Different structural models of the
graphene-Mn-Cu(111) interface are investigated. While a Mn monolayer placed
between graphene and Cu(111) (an unfavorable configuration) yields massive
rearrangement of the graphene-derived $\pi$ bands in the vicinity of the Fermi
level, the possible formation of a Cu$_2$Mn alloy at the interface (a favorable
configuration) preserves the linear dispersion for these bands. The deep
analysis of the electronic states around the Dirac point for the
graphene/Cu$_2$Mn/Cu(111) system allows to discriminate between contributions
from three carbon sublattices of a graphene graphene layer in this system and
to explain the bands' as well as spins' topology of the electronic states
around the Fermi level.
