Being homologue to the new, Fe-based type of high-temperature superconductors, CeFePO exhibits magnetism, Kondo and heavy-fermion phenomena. We experimentally studied the electronic structure of CeFePO by means of angle-resolved photoemission spectroscopy. In particular, contributions of the Ce 4f-derived states and their hybridization to the Fe 3d bands were explored using both symmetry selection rules for excitation and their photoionization cross-section variations as a function of photon energy. It was experimentally found - and later on confirmed by LDA as well as DMFT calculations - that the Ce 4f states hybridize to the Fe 3d states of d_{3z^2-r^2} symmetry near the Fermi level that discloses their participation in the occurring electron-correlation phenomena and provides insight into mechanism of superconductivity in oxopnictides.
@article{arxiv.1006.0583,
title = {CeFePO: f-d hybridization and quenching of superconductivity},
author = {M. G. Holder and A. Jesche and P. Lombardo and R. Hayn and D. V. Vyalikh and S. Danzenbächer and K. Kummer and C. Krellner and C. Geibel and Yu. Kucherenko and T. Kim and R. Follath and S. L. Molodtsov and C. Laubschat},
journal= {arXiv preprint arXiv:1006.0583},
year = {2010}
}