Recent progress of soft X-ray photoelectron spectroscopy studies of uranium compounds

Abstract

Recent progresses in the soft X-ray photoelectron spectroscopy (PES) studies (hν≳100eV) for uranium compounds are briefly reviewed. The soft X-ray PES has enhanced sensitivities for the bulk U5f electronic structure, which is essential to understand the unique physical properties of uranium compounds. In particular, the recent remarkable improvement in energy resolutions from an order of 1eV to 100meV made it possible to observe fine structures in U5f density of states. Furthermore, soft X-ray ARPES becomes available due to the increase of photon flux at beamlines in third generation synchrotron radiation facilities.The technique made it possible to observe bulk band structures and Fermi surfaces of uranium compounds and therefore, the results can be directly compared with theoretical models such as band-structure calculations. The core-level spectra of uranium compounds show a systematic behavior depending on their electronic structures, suggesting that they can be utilized to determine basic physical parameters such as the U5f-ligand hybridizations or Comlomb interaction between U5f electrons. It is shown that soft X-ray PES provides unique opportunities to understand the electronic structures of uranium compounds.