UC Irvine

A series of cerium heavy fermion compounds have been studied in order to check for the systematics with TK and the temperature dependence of the Kondo resonance predicted by the Kondo model. Neither the systematics nor the temperature dependence is found, the latter primarily determined from a detailed study in CeSi2. The qualitative shapes of the features at EF remain nearly constant irrespective of TK, while all the temperature dependence can be explained as resulting from phonon broadening of core-like states as well as Fermi function broadening. In addition, if the d electron contribution to the spectra is subtracted, one obtains a symmetric, lorentzian line shape for the "main" 4f peak. © 1992.