Anisotropic hybridization in CeRhSn

TL;DR

This study investigates the anisotropic electronic structure and temperature-dependent spectral weight transfer in CeRhSn, revealing its mixed valence nature and the emergence of a coherent Kondo state through combined experimental and theoretical approaches.

Contribution

It provides new insights into the anisotropic optical conductivity and the role of electronic correlations in CeRhSn, integrating broadband spectroscopy with advanced theoretical modeling.

Findings

CeRhSn exhibits spectral weight transfer over high energy and temperature scales.

The optical conductivity shows substantial anisotropy in the electronic structure.

Theoretical models successfully reproduce the spectroscopic signatures, highlighting the role of electronic correlations.

Abstract

The optical conductivity $\sigma(\omega,T)$ of CeRhSn was studied by broadband infrared spectroscopy. Temperature-dependent spectral weight transfer occurs over high energy ($0.8\,$eV) and temperature (${\sim}500\,$K) scales, classifying CeRhSn as a mixed valent compound. The optical conductivity reveals a substantial anisotropy in the electronic structure. Renormalization of $\sigma(\omega,T)$ 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 $>10\,$meV 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.