Photoemission and inverse-photoemission study of CeNiSn

We have measured soft X-ray inverse-photoemission, Ce 3d-4f resonant photoemission and Ce 3d X-ray absorption spectra of CeNiSn, which is known as a Kondo semimetal, in order to clarify the possible difference of the surface Ce valency from the bulk one and its effect on the photoemission spectra. We have analyzed the spectra by model calculations based on the Anderson-impurity model with the assumption that the spectra are the superposition of the bulk and surface components and obtained the bulk and surface parameter sets of the model Hamiltonian. High-resolution photoemission spectra are also presented to observe the low-energy-scale electronic structure.