  The interlayer coupling of twisted bilayer graphene could markedly affect its
electronic band structure. A current challenge required to overcome in
experiment is how to precisely control the coupling and therefore tune the
electronic properties of the bilayer graphene. Here, we describe a facile
method to modulate the local interlayer coupling by adsorption of single
molecule magnets onto the twisted bilayer graphene and report the
characterization of its electronic band structure using scanning tunneling
microscopy and spectroscopy. The low-energy Van Hove singularities (VHSs) and
superlattice Dirac cones, induced by the interlayer coupling and
graphene-on-graphene moir\'e respectively, are observed in the tunneling
spectra. Our experiment demonstrates that the energy difference of the two
VHSs, which reflects the magnitude of interlayer coupling, can be tuned by the
local coverage density of adsorption.
