Electronic structure of UAsSe and USb2 compounds: the 5f photoemission

ABSTRACTUAsSe and USb2 single crystals were studied at 15K by angle-resolved photoemission spectroscopy (ARPES) in the photon energy range between 20 eV and 110 eV. The high energy and momentum resolution (24 meV and 0.09Å−1, respectively) allows observation of very narrow and dispersive photoemission features within 100 meV of the Fermi level. The natural linewidth of the near EF feature of USb2 was found to be less than 10 meV with the dispersion of 10 meV observed in normal emission spectra. The near EF feature in UAsSe is slightly broader, situated closer to the Fermi edge, and exhibits 20 meV dispersion in the normal emission spectra. It gives evidence that neither UAsSe nor USb2 have purely 2D electronic structure. Both these compounds should be treated as quasi-2D materials.