Raman spectroscopy of f -electron metals: An example of CeB6

We performed an optical spectroscopy study of electronic and magnetic excitations for a rare-earth system with a single electron quasilocalized in the f shell on an ion at high-symmetry crystallographic site in application to CeB6 heavy-fermion metal. We carried out group-theoretical classification of the electronic crystal field (CF) transitions and assessed their coupling to light cross sections for polarization resolved Raman scattering processes. We discuss applicability of symmetrized Raman susceptibility to studies of exotic charge and spin high multiplet ordering phases in f-electron systems. We study temperature effects on intra- and intermultiplet CF transitions and also on the coupling between the CF excitations with the lattice vibrations. We acquired temperature dependence of the low-frequency polarization resolved Raman response for all Raman-allowed symmetry channels: A1g, Eg, T1g, and T2g of the cubic Oh point group. We demonstrate that T1g-symmetry static Raman susceptibility shows a temperature dependence which is consistent with the previously-reported magnetic susceptibility data. Such behavior in the T1g channel signifies the presence of long wavelength magnetic fluctuations, which is interpreted as a manifestation of ferromagnetic correlations induced by tendency towards quadrupolar ordering.