Crystal-field and configuration dependence of hopping-matrix elements forCeCu2Si2

The hopping-matrix elements ${\mathit{V}}_{\mathit{m}}$(ɛ) between the conduction states with energy ɛ and the different crystal-field-split 4f states m are calculated for ${\mathrm{CeCu}}_2$ ${\mathrm{Si}}_2$. With use of the Anderson impurity model, the effect of this m dependence on the static T=0 K susceptibility is studied. We also take into account that the one-particle hopping-matrix elements entering in the ${\mathit{f}}^0$→${\mathit{f}}^1$ and the ${\mathit{f}}^1$→${\mathit{f}}^2$ hopping processes are different (configuration dependence). It is concluded that for ${\mathrm{CeCu}}_2$ ${\mathrm{Si}}_2$ larger hopping-matrix elements are needed for the description of thermodynamic properties than for spectroscopic properties. These results are consistent with renormalization effects, which the Coulomb interaction between the 4f and conduction electrons is expected to cause.