Anisotropic hybridization in CeRhSn

The optical conductivity σ(ω,T) of CeRhSn was studied by broadband infrared spectroscopy. Temperature-dependent spectral weight transfer occurs over high energy (0.8eV) and temperature (∼500K) scales, classifying CeRhSn as a mixed-valent compound. The optical conductivity reveals a substantial anisotropy in the electronic structure. Renormalization of σ(ω,T) occurs as a function of temperature to a coherent Kondo state with concomitant effective mass generation. Associated spectroscopic signatures were reproduced remarkably well by the combination of density functional theory and dynamical mean-field theory using a momentum-independent self-energy. The theory shows that the anisotropy for energies >10meV is mainly driven by the bare three-dimensional electronic structure that is renormalized by local electronic correlations. The possible influence of magnetic frustration and quantum criticality is restricted to lower energies.