High-resolution photoemission study of the low-energy excitations in 4f-electron systems

We present an extensive photoemission study of the low-energy excitations in a series of Ce and Yb systems showing quite different electronic properties resulting from the weak hybridization of the 4f electrons with band states. We discuss briefly the application of the single-impurity model to the calculation of the excitation spectra and review the influence of the different parameters. We analyze the spectra of each compound separately and show that they can be remarkably well simulated within the single-impurity framework. From these data we attempt to predict the linear coefficient of the specific heat and the magnetic susceptibility at T=0 K. A comparison with experimental values points to the limitations of this model to yield a unified description of different properties.