Valence band of Ce2Co0.8Si3.2 and Ce2RhSi3 studied by resonant photoemission spectroscopy and FPLO calculations

Abstract

This work presents studies of the valence band of two Kondo lattice systems: Ce2Co0:8Si3:2, which is paramagnetic with the Kondo temperature TK 50 K and Ce2RhSi3, which is antiferromagnetic below TN = 4:5 K and exhibits TK 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 (EF), its spin orbit splitting partner at 0.24 eV and a broad maximum related to Ce f0 nal state. The spectra indicate that Kondo peak has a higher intensity for Ce2Co0:8Si3:2. The o -resonance photoemission data reveal that a maximum in the 3d electron density of states is shifted towards EF for Ce2Co0:8Si3:2 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 EF 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.