Emergence of Kondo Resonance in Graphene Intercalated with Cerium.

Hwang, Jinwoong; Kim, Kyoo; Ryu, Hyejin; Kim, Jingul; Lee, Ji-Eun; Kim, Sooran; Kang, Minhee; Park, Byeong-Gyu et al. · Nano Lett · 2018

basic_science · Level V

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Abstract

The interaction between a magnetic impurity, such as cerium (Ce) atom, and surrounding electrons has been one of the core problems in understanding many-body interaction in solid and its relation to magnetism. Kondo effect, the formation of a new resonant ground state with quenched magnetic moment, provides a general framework to describe many-body interaction in the presence of magnetic impurity. In this Letter, a combined study of angle-resolved photoemission (ARPES) and dynamic mean-field theory (DMFT) on Ce-intercalated graphene shows that Ce-induced localized states near Fermi energy, E<sub>F</sub>, hybridized with the graphene π-band, exhibit gradual increase in spectral weight upon decreasing temperature. The observed temperature dependence follows the expectations from the Kondo picture in the weak coupling limit. Our results provide a novel insight how Kondo physics emerges in the sea of two-dimensional Dirac electrons.