Electronic States of UNi2 from Photoemission Spectroscopy

R. Zalecki a, A. Kołodziejczyk a, N.-T.H. Kim-Ngan b, A. Adamska b, A. Kowalczyk c, T. Toliński c and M. Mihalik d a Department of Solid State Physics, AGH University of Science and Technology, 30-059 Cracow, Poland b Institute of Physics, Pedagogical University, 30-084 Cracow, Poland c Institute of Molecular Physics, PAS, 60-179 Poznań, Poland d Institute of Experimental Physics, SAS, 040 01 Košice, Slovakia

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Received: 9 07 2007;

We measured the angle-resolved ultraviolet and X-ray photoemission spectra of UNi2 single crystal. The valence band angle-resolved ultraviolet photoemission spectra were compared to the accessible band structure calculations. For UNi2 the lowest binding energy strong emission at about -0.1 eV comes from U 5f states and overlaps with the Fermi edge. A small feature at -0.6 eV was ascribed also to U 5f electrons with more localised character. The higher-energy two-peak structure at about -1.2 eV and -2.1 eV comes from Ni 3d states. X-ray photoemission spectroscopy shows the standard two-line spin-orbit splitting of the Ni 2p states and of the U 4f states. Some hybridisation of the Ni 3d and U 5f state was observed in the spectra. The pronounced satellites to the Ni 2p and 3p states, associated with the on-site Coulomb repulsion and other electron correlation energies, were observed.

DOI: 10.12693/APhysPolA.113.407 PACS numbers: 71.20.Lp, 79.60.Bm, 71.15.Ap