Abstract
We present core level nonresonant inelastic x-ray scattering (NIXS) data of the heavy-fermion compounds and measured at the Ce edges. The higher than dipole transitions in NIXS allow determining the orientation of the crystal-field ground-state orbital within the unit cell. The crystal-field parameters of the compounds and related substitution phase diagrams have been investigated in great detail in the past; however, whether the ground-state wave function is the or orientation) remained undetermined. We show that the doublet with lobes along the (110) direction forms the ground state in and . For , however, we find also some contribution of the first excited state crystal-field state in the ground state due to the stronger hybridization of and conduction electrons, suggesting a smaller value than originally anticipated from x-ray absorption. A comparison is made to the results of existing density functional theory plus dynamical mean-field theory calculations.
- Received 18 February 2019
- Revised 22 May 2019
DOI:https://doi.org/10.1103/PhysRevB.99.235143
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