Emergence of Kondo Resonance in Graphene Intercalated with Cerium

The interaction of a magnetic impurity with surrounding electrons has been a core problem in modern physics to understand fundamentals of many-body effects and its relation to magnetism. In particular, antiferromagnetic screening of the local magnetic moment by conduction electrons leads to the formation of a new resonant-type many-body ground state, so-called Kondo resonance. Here we report the realization of the Kondo resonance in a prototypical two-dimensional system, graphene, induced by the presence of cerium with the localized spin of a 4felectron. The combination of two complementary techniques, angle-resolved photoemission spectroscopy and dynamic mean-field theory, reveals the development of new spectral weight near Fermi energy at lower temperature that is hybridized with the graphene π-band. The observed T-dependence provides not only a direct evidence of the formation of the many-body ground state in graphene, but also novel insight how Kondo physics emerges in the sea of two-dimensional Dirac electrons.