A key issue in heavy fermion research is how subtle changes in the hybridization between the 4f (5f) and conduction electrons can result in fundamentally different ground states. CeRhIn5 stands out as a particularly notable example: replacing Rh by either Co or Ir, located above or below Rh in the periodic table, antiferromagnetism gives way to superconductivity. In this photoemission study of CeRhIn5, we demonstrate that the use of resonant ARPES with polarized light allows to extract detailed information on the 4f crystal field states and details on the 4f and conduction electron hybridization which together determine the ground state. We directly observe weakly dispersive Kondo resonances of f-electrons and identify two of the three Ce 4f5/21 crystal-electric-field levels and band-dependent hybridization, which signals that the hybridization occurs primarily between the Ce 4f states in the CeIn3 layer and two more three-dimensional bands composed of the Rh 4d and In 5p orbitals in the RhIn2 layer. Our results allow to connect the properties observed at elevated temperatures with the unusual low-temperature properties of this enigmatic heavy fermion compound.
@article{arxiv.1801.07797,
title = {Band dependent inter-layer $f$-electron hybridization in CeRhIn$_5$},
author = {Q. Y. Chen and D. F. Xu and X. H. Niu and R. Peng and H. C. Xu and C. H. P. Wen and X. Liu and L. Shu and S. Y. Tan and X. C. Lai and Y. J. Zhang and H. Lee and V. N. Strocov and F. Bisti and P. Dudin and J. -X. Zhu and H. Q. Yuan and S. Kirchner and D. L. Feng},
journal= {arXiv preprint arXiv:1801.07797},
year = {2019}
}