Determining the local low-energy excitations in the Kondo semimetal CeRu4Sn6 using resonant inelastic x-ray scattering

Abstract

We have investigated the local low-energy excitations in CeRu4Sn6, a material discussed recently in the framework of strongly correlated Weyl semimetals, by means of Ce M5 resonant inelastic x-ray scattering (RIXS). The availability of both 2F 5 2 and 2F 7 2 excitations of the Ce 4f 1 configuration in the spectra allows for the determination of the crystal-electric field parameters that explain quantitatively the temperature dependence and anisotropy of the magnetic susceptibility. The absence of an azimuthal dependence in the spectra indicates that all crystal-electric field states are close to being rotational symmetric. We show further that the non-negligible impact of the Aˇ0 6 parameter on the ground state of CeRu4Sn6 leads to a reduction of the magnetic moment due to multiplet intermixing. The RIXS results are consistent with inelastic neutron scattering (INS) data and are compared to the predictions from ab-initio based electronic structure calculations.