ACTA

Valence Band of Ce₂Co_0.8Si_3.2 and Ce₂RhSi₃ Studied by Resonant Photoemission Spectroscopy and FPLO Calculations

P. Starowicz^a, R. Kurleto^a, J. Goraus^b, Ł. Walczak^a,c, B. Penc^a, J. Adell^d, M. Szlawska^e, D. Kaczorowski^e and A. Szytuła^a
^aM. Smoluchowski Institute of Physics, Jagiellonian University, W.S. Reymonta 4, 30-059 Kraków, Poland
^bInstitute of Physics, University of Silesia, Uniwersytecka 4, 40-007 Katowice, Poland
^cDepto. de Fisica de la Materia Condensada, Universidad Autónoma de Madrid, Madrid, Spain
^dMAX-Lab, Lund University, 221 00 Lund, Sweden
^eInstitute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, 50-950 Wrocław, Poland

Full Text PDF

This work presents studies of the valence band of two Kondo lattice systems: Ce₂Co_0.8Si_3.2, which is paramagnetic with the Kondo temperature T_K ≈50 K and Ce₂RhSi₃, which is antiferromagnetic below T_N=4.5 K and exhibits T_K ≈9 K. The photoemission spectra, which are obtained with photon energy tuned to Ce 4d-4f resonance, reveal a Kondo peak at the Fermi energy (E_F), its spin-orbit splitting partner at 0.24 eV and a broad maximum related to Ce f⁰ final state. The spectra indicate that Kondo peak has a higher intensity for Ce₂Co_0.8Si_3.2. The off-resonance photoemission data reveal that a maximum in the 3d electron density of states is shifted towards E_F for Ce₂Co_0.8Si_3.2 as compared to Ce₂RhSi₃. Full-potential local-orbital calculations were realized with local spin density approach +U approach for 213 stoichiometry. They show that a higher density of states near E_F is observed for Ce₂CoSi₃. The calculations also reveal the existing tendencies for antiferromagnetic and ferromagnetic ground states in a case of Ce₂RhSi₃ and Ce₂CoSi₃, respectively.

DOI: 10.12693/APhysPolA.126.A-144
PACS numbers: 71.27.+a, 75.30.Mb, 71.20.Eh, 74.25.Jb