Advanced Line Shape Analysis of Core to Valence Resonant Inelastic X-Ray Scattering spectra for Ce-based Kondo Materials

Recently investigations of f -f transitions in Ce-based Kondo compounds became possible with the use of Resonant Inelastic X-Ray Scattering (RIXS) [1]. Due to the high flux one can not only investigate the energy of the f -f transitions, but also perform a line-shape analysis. The same hybridization interaction responsible for the formation of the Kondo ground state turns the f -f transitions into resonances with strongly hybridization-dependent asymmetric line-shapes [2]. We here present results on CeBa7Au6Si40 and CeRu4Sn6, compounds with a very low (≈1 K) [3] and a somewhat higher (≈6 K) Kondo temperature [4].

With the aid of density functional theory-based dynamical mean-field theory calculations using Quanty (www.Quanty.org) we can relate the line shape of the f -f transitions to the hybridization function in these materials. Theoretically obtained hybridization functions from DFT agree reasonably, albeit not perfectly,

with the experimentally determined interactions. Our results show a direct relation between the hybridization function, the Kondo temperature, and crystal fields present in these two materials.

[1] L. J. P. Ament et al., Rev. Mod. Phys. 83, 705–767 (2011).

[2] A. Amorese et al., Phys. Rev. B 98, 081116(R) (2018).

[3] A. Prokofiev et al., Nat. Mater. 12, 1096 (2013).

[4] A. M. Strydom et al., Physica B 359–361, 293 (2005).