  The electronic structure of the Kondo lattice CeIn3 has been studied by
on-resonant angle-resolved photoemission spectroscopy and scanning tunneling
microscopy/spectroscopy. A weakly dispersive quasiparticle band has been
observed directly with an energy dispersion of 4 meV by photoemission, implying
the existence of weak hybridization between the f electrons and conduction
electrons. The hybridization is further confirmed by the formation of the
hybridization gap revealed by temperature-dependent scanning tunneling
spectroscopy. Moreover, we find the hybridization strength in CeIn3 is much
weaker than that in the more two-dimensional compounds CeCoIn5 and CeIrIn5. Our
results may be essential for the complete microscopic understanding of this
important compound and the related heavy-fermion systems.

Strongly Correlated Electrons