Crystal-field splitting in CeB6 observed by ultrahigh-resolution photoemission spectroscopy

We report ultrahigh-resolution (DeltaE=8 meV) photoemission spectroscopy on CeB6 to study the electronic structure and the crystal-held splitting. The photoemission spectrum of CeB6 near E-F shows two prominent structures; a broad one near E-F and a relatively sharp peak at 280 meV. The former is as cribed to the "Kondo resonance peak" at E-F while the latter being from the spin-orbit satellite (Ce 4f(7/2)). In the broad structure near E-F, we cle arly observed an additional small structure around 60 meV from E-F. Numeric al simulations based on the single-impurity Anderson model with non-crossin g approximation show that this satellite is due to the crystal-held splitti ng (Gamma (S)-Gamma (7)) of the Ce 4f(5/2) state. (C) 2001 Elsevier Science B;V. All rights reserved.