Resonant photoemission studies of the Kondo-lattice systems CeCu2Si2, CeAg2Si2, CeAu2Si2, and CePd2Si2

Abstract

Photoemission experiments performed at an incident photon energy of 70 eV provide a clear view of the transition-element-derived d bands in the systems CeT2Si2, with T=Cu,Ag,Au,andPd. Spectra taken at h=122 eV display both a resonant 4f emission at 2-3 eV below EF, and a resonant emission near EF. The total intensity of the latter feature, which has been observed in other Ce-based systems and identified as having strong 4f character in -cerium and CeAl2, appears to track the intensities of the transition-element-derived d density of states near EF. In superconducting CeCu2Si2, the EF feature has its maximum at 0.25 eV, whereas we find it at significantly higher binding energies (0.6 eV) in the three magnetic systems (T=Ag,Au,andPd). This observation suggests markedly smaller electronic specific-heat () values in the magnetic compounds as compared with 1 J mole-1 K-2 generated by heavy fermions in CeCu2Si2. © 1983 The American Physical Society.