ELECTRON-SPECTROSCOPY STUDIES OF SCALING BEHAVIORS IN HEAVY FERMIONS

We present in this paper photoemission and inverse photoemission measu rements of several Ce- and Yb-based compounds. Scaling behaviours char acteristic of the Kondo effect are clearly observed: in the CeSi(x) se ries, the modification of the Kondo temperature with stoichiometry is accompanied by a decrease of spectral weight near E(F) in photoemissio n and inverse photoemission. Moreover, the 4f spectral density of seve ral Ce- and Yb-based compounds exhibits the temperature dependence exp ected in the Anderson model. These measurements show that the Anderson model contains the fundamental mechanisms accounting for the spectros copic properties of Kondo systems.