  Although the single-impurity Kondo physics has already been well understood,
the understanding of the Kondo lattice problem where a dense array of local
moments couples to the conduction electrons is still far from complete. The
ability of creating and tuning the Kondo lattice in non-f-electron systems will
be great helpful for further understanding the Kondo lattice behavior. Here we
show that the Pb intercalation in the charge-density-wave-driven
narrow-electronic-band system 1T-TaS2 induces a transition from the insulating
gap to a sharp Kondo resonance in the scanning tunneling microscopy
measurements. It results from the Kondo screening of the localized moment in
the 13-site Star-of-David clusters of 1T-TaS2, and thus confirms the cluster
Mott localization of the unpaired electrons and local moment formation in the
1T-TaS2 layer. As increasing the Pb concentration, the narrow electronic band
derived from the localized electrons shifts away from the Fermi level and the
Kondo resonance peak is gradually suppressed. Our results pave a way for
creating and tuning many-body electronic states in layered
narrow-electronic-band materials.

Strongly Correlated Electrons;Mesoscale and Nanoscale Physics