UC Irvine

The electronic structure of both Ce and U heavy fermions appears to consist of extremely narrow, nearly temperature-independent bands (i.e., no spectral weight loss or transfer with temperature). A small dispersion of the f-bands above the Kondo temperature is easily measurable so that a Kondo resonance, as defined by NCA, is not evident. Preliminary results, however, indicate that the Periodic Anderson Model (PAM) captures some of the essential physics. Angle-integrated resonant photoemission results on δ-Pu indicate a narrow 5f feature at EF, similar in width to f-states in Ce and U compounds, but differing in that PES cross-section as a function of hv suggests substantial 6d admixture. © 1998 Elsevier Science S.A.