Competition between heavy-fermion and Kondo interaction in isoelectronic A-site ordered perovskites
arXiv:1404.6137 · doi:10.1038/ncomms6818
Abstract
With current research efforts shifting towards the 4 and 5 transition metal oxides, understanding the evolution of the electronic and magnetic structure as one moves away from 3 materials is of critical importance. Here we perform X-ray spectroscopy and electronic structure calculations on -site ordered perovskites with Cu in the -site and the -sites descending along the 9th group of the periodic table to elucidate the emerging properties as -orbitals change from partially filled 3, 4, to 5. The results show that when descending from Co to Ir the charge transfers from the cuprate like Zhang-Rice state on Cu to the t orbital of the B site. As the Cu -orbital occupation approaches the Cu limit, a mixed-valence state in CaCuRhO and heavy fermion state in CaCuIrO are obtained. The investigated d-electron compounds are mapped onto the Doniach phase diagram of the competing RKKY and Kondo interactions developed for f-electron systems.
4 pages, 4 figures