Fig. 4: Spinon Kondo effect of MnPc molecules on monolayer 1T-NbSe2.
a, b Site-dependent STS spectra recorded on pristine monolayer 1T-NbSe2 as well as on MnPc-top and MnPc-hollow, as marked in the inset. The new resonance peaks indicated by arrows appear at the band edges, which arise from the spinon Kondo effect. c Theoretical simulation of the electronic DOS that exhibits the emergence of band edge resonance peaks. The DOS in red corresponds to a local magnetic impurity involved in both holon-spinon hole binding and doublon-spinon binding. The DOS in blue corresponds to the case with only doublon-spinon binding. The DOS in black is the electronic DOS of the pristine QSL. The resonance peaks appear at the band edges, with their strength varying with the spin-charge binding interaction. d Energy diagram of the band edge resonance states. e Physical mechanism of the interaction between a QSL state and a local magnetic moment. A magnetic impurity in a QSL candidate can result in a spinon Kondo screening cloud (brown shadow). Such a cloud attracts a chargon in QSL under the spin-charge binding interaction.
