Photoemission spectra of CeAl3, CeBe13, CeSi2, and CeCu2Si2: Weights and widths of the 4f emission features.

Abstract

We present valence-band photoemission spectra for CeAl3, CeBe13, CeSi2, CeCu2Si2, and related conventional rare-earth counterpart compounds, taken at photon energies corresponding to the giant 4d resonance with resolution ∼150 meV. We take into account the 5d emission, which comprises 30% of the valence-band emission at the 4d resonance. We compare the resulting 4f emission to the predictions of the Anderson impurity model calculated in a low-order 1/N expansion, and including spin-orbit, crystal-field, and finite Coulomb correlation effects. The calculation gives order-of-magnitude fits to the data, but underestimates the spectral weight near the Fermi level by a factor of 2 and overestimates the width of the main f emission at 2 eV by a factor of 4. We argue that Ce photoemission remains an open problem and discuss several experimental and theoretical issues which need to be resolved to make further progress. © 1993 The American Physical Society