  The electronic and crystallographic structure of the graphene/Rh(111) moir\'e
lattice is studied via combination of density-functional theory calculations
and scanning tunneling and atomic force microscopy (STM and AFM). Whereas the
principal contrast between hills and valleys observed in STM does not depend on
the sign of applied bias voltage, the contrast in atomically resolved AFM
images strongly depends on the frequency shift of the oscillating AFM tip. The
obtained results demonstrate the perspectives of application atomic force
microscopy/spectroscopy for the probing of the chemical contrast at the
surface.
