Emergence of Kondo resonance in graphene intercalated with cerium

TL;DR

This study demonstrates the emergence of Kondo resonance in Ce-intercalated graphene, revealing how magnetic impurity interactions lead to many-body effects in two-dimensional Dirac electron systems.

Contribution

It combines ARPES and DMFT to show the development of Kondo physics in graphene with cerium impurities, a novel observation in 2D materials.

Findings

Localized states near Fermi energy hybridize with graphene π band

Spectral weight increases with decreasing temperature

Results align with weak coupling Kondo physics expectations

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, $E_{\rm F}$, hybridized with the graphene $\pi$ 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.