Orbital selective coupling in CeRh${}_3$B${}_2$: co-existence of high Curie and high Kondo temperature

Abstract

We investigated the electronic structure of the enigmatic CeRh${}_3$B${}_2$ using resonant inelastic scattering and x-ray absorption spectroscopy in combination with $ab$ $initio$ density functional calculations. We find that the Rh 4$d$ states are irrelevant for the high-temperature ferromagnetism and the Kondo effect. We also find that the Ce 4$f$ crystal-field strength is too small to explain the strong reduction of the Ce magnetic moment. The data reveal instead the presence of two different active Ce 4$f$ orbitals, with each coupling selectively to different bands in CeRh${}_3$B${}_2$. The inter-site hybridization of the |J=5/2,Jz=+/-1/2> crystal-field state and Ce 5$d$ band combined with the intra-site Ce 4$f$-5$d$ exchange creates the strong ferromagnetism, while hybridization between the |J=5/2,Jz=+/-5/2> 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 CeRh${}_3$B${}_2$.

15 pages, 14 figures

References in corpus (5)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Determining the crystal-field ground state in rare earth Heavy Fermion materials using soft-x-ray absorption spectroscopy
• Possible multi-orbital ground state in CeCu${}_2$Si${}_2$
• Variational Mote Carlo Study of Flat Band Ferromagnetism -- Application to CeRh_3 B_2
• Investigation of metamagnetism and crystal-field splitting in pseudo-hexagonal CeRh${}_3$Si${}_2$

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• The Kondo effect in ferromagnetic quantum critical CeRh${}_6$Ge${}_4$
• Distinct effect of Kondo physics on crystal field splitting in electron and spin spectroscopies