  The Kondo effect typically arises from the spin-flip scattering between the
localized magnetic moment of the impurity and the delocalized electrons in the
metallic host, which leads to a variety of intriguing phenomena. Here, by using
scanning tunnelling microscopy/spectroscopy (STM/STS), we present the Kondo
effect and subatomic features of single U adatom on graphene/6H-SiC(0001). A
dip spectral feature can be observed around the Fermi energy, which is termed
as the "fingerprint" of the Kondo resonance in STS; in addition, two subatomic
features with different symmetries: a three-lobe structure and a donghnut-like
structure can be observed from the dI/dV maps. The Kondo resonance is only
detectable within 5~\AA~of the lateral distance from the U atom center, which
is much smaller than the distances observed in Co atoms on different surfaces,
indicating the more localized 5$f$ states than 3$d$ orbitals. By comparing with
density functional theory calculations, we find that the two subatomic features
displaying different symmetries originate from the selective hybridization
between U 6$d$, 5$f$ orbitals and the $p_z$ orbitals from two inequivalent C
atoms of the multilayer graphene.
