CRYSTAL-FIELD EXCITATIONS IN CECU2SI2

An inelastic-neutron-scattering investigation of the dynamic magnetic susceptibility of the heavy-fermion compound CeCu2Si2 is presented. We find evidence for only one crystal-field (CF) transition at specific-heat results but in contradiction with two earlier neutron-scattering studies. Using other experimental results, we propose a set of CF parameters (B2(0)=-1.29+/-0.06 meV, B4(0)=(-4.3+/-0.2) X 10(-3) meV, \B-4(4)\=0.45+/-0.02 meV) which describe satisfactorily all the measured properties that depend on the CF. A simple CF model is adequate to describe most of the observed features of this system at temperatures well above the Kondo temperature although the width of the observed transition is anomalously large. A comparison of the CF parameters with other isostructural compounds gives the clearest evidence so far that hybridization between the cerium f electrons and the silicon p electrons is mainly responsible for the CF potential itself.