Direct observation of a quasiparticle band in the antiferromagnetic Kondo lattice CeIn₃

The electronic structure of the In layer-terminated Kondo lattice CeIn₃ has been studied by on-resonant angle-resolved photoemission spectroscopy with improved resolution. A weakly dispersive quasiparticle band has been observed directly with an energy dispersion of 4 meV, indicating the existence of weak hybridization between the f electrons and conduction electrons. Both the conduction bands (α and β) and f band exhibit the same dichroic response to different circularly polarized lights, providing a prerequisite for the hybridization between them. The c-f hybridization strength in CeIn₃ is much weaker than in the more two-dimensional compounds CeCoIn₅ and CeIrIn₅. Our results suggest that the 4f states in CeIn₃ are dominated by the localized character, with a small itinerant component.