Observation of Kondo Resonance and Low-Energy Excitation in CeB₆ Using Point-Contact Spectroscopy

We performed point-contact spectroscopy on CeB6, a heavy fermion compound, using superconducting Nb as a probe tip to achieve high-precision measurements. The differential conductance spectrum represents a sharp zero-bias conductance peak (ZBCP) below T similar to 6 K. The temperature dependence of the spectra reveals that the ZBCP intensity increases logarithmically with decreasing temperature, owing to the evolution of Kondo resonance. A double-peak structure reflecting the indirect hybridization gap was not observed, suggesting that the development of Kondo lattice coherence is prevented by the emergence of antiferroquadrupolar and/or antiferromagnetic orderings.