  We have used Ultrahigh Vacuum (UHV) Scanning tunneling microscopy (STM) to
investigate the effect of thermal annealing of graphene grown by chemical
vapour deposition (CVD) on a Cu(110) foil. We show that the annealing appears
to induce a reconstruction of the Cu surface along the [210] direction, with a
period of 1.43 nm. Such reconstructions have been ascribed to the tensile
strain induced in the Cu surface by differential thermal expansion of it
relative to the graphene overlayer, but we show that it is in fact a Moir\'e
pattern due to interference between the graphene and the underlying atomic
lattice as evidenced by the appearance of an odd-even transition only observed
due to mis-orientation of the top layer of a crystal. This highlights that the
analysis of STM measurements of graphene on metal surfaces should take such
interference into account and that the graphene-Cu interface is more complex
than previously thought.
