SPECTROSCOPIC EVIDENCE OF A KONDO SCALE IN CERIUM COMPOUNDS

We present a high-resolution photoemission (PES) and temperature-dependent inverse photoemission (BIS) investigation of Ce compounds, and in particular, of the paradigmatic system CeSix. The PES intensity near the Fermi level follows, as in the calculated spectral function of the Anderson Hamiltonian, the evolution of the Kondo temperature T(K) In BIS, the predicted collapse of the Kondo resonance reflects the breakdown of the singlet ground state above T(K). These results provide an important confirmation of the validity of the Kondo model of cerium compounds, and contradict recent claims of inconsistencies with spectroscopic data.