Weak hybridization effects revealed by ARPES in heavy-fermion Ce₂IrIn₈

We utilize high resolution on-resonant (hv~120eV) angle-resolved photoemission spectroscopy (ARPES) to study the band structure and hybridization effect of heavy-fermion compound Ce₂IrIn₈. Hybridization between 4f electron and conduction electron plays a significant role on the behavior of heavy-fermion compounds. Band structure experiments fit well with the results of DFT calculation. We observe obvious flat band below coherent temperature T_coh~40 K which characterize electrical resistance maxima indicate the onset temperature of hybridization. But the Fermi surface (FS) volume and Fermi vector k_F don't change largely, which challenge the widely believed evolution from high temperature small FS to low temperature big FS.