Orbital selective coupling in CeRh3 B2: Coexistence of high Curie and high Kondo temperatures

Abstract

We investigated the electronic structure of the enigmatic CeRh3B2 using resonant inelastic scattering and x-ray absorption spectroscopy in combination with ab initio density functional calculations. We find that the Rh4d states are irrelevant for the high-temperature ferromagnetism and the Kondo effect. We also find that the Ce4f crystal-field strength is too small to explain the strong reduction of the Ce magnetic moment. The data revealed instead the presence of two different active Ce4f orbitals, with each coupling selectively to different bands in CeRh3B2. The intersite hybridization of the |J=52,Jz=±12) crystal-field state and Ce5d band combined with the intrasite Ce4f-5d exchange creates the strong ferromagnetism, while hybridization between the |J=52,Jz=±52) and the B sp in the ab-plane contributes to the Kondo interaction, which causes the moment reduction. This orbital selective coupling explains the unique and seemingly contradictory properties of CeRh3B2.