4fexcitations in Ce Kondo lattices studied by resonant inelastic x-ray scattering

Abstract

The potential of resonant inelastic soft x-ray scattering to measure 4f crystal electric-field excitation spectra in Ce Kondo lattices has been examined. Spectra have been obtained for several Ce systems and show a well-defined structure determined by crystal-field, spin-orbit, and charge-transfer excitations only. The spectral shapes of the excitation spectra can be well understood in the framework of atomic multiplet calculations. For CeCu 2 Si 2 we found notable disagreement between the inelastic x-ray-scattering spectra and theoretical calculations when using the crystal-field scheme proposed from inelastic neutron scattering. Modified sets of crystal-field parameters yield better agreement. Our results also show that, with the very recent improvements of soft x-ray spectrometers in resolution to below 30 meV at the Ce M 4,5 edges, resonant inelastic x-ray scattering could be an ideal tool to determine the crystal-field scheme in Ce Kondo lattices and other rare-earth compounds.

Crystal Growth of Materials with the ThCr2Si2 Structure Type

“…This energy scale is also visible in the magnetic susceptibility again as a broad maximum at around 200 K (Figure b). The intermediate valence of Ce in this compound was recently directly confirmed by X‐ray absorption spectroscopy and resonant inelastic X‐ray scattering . The magnetic anisotropy of CeRu 2 P 2 is reversed to CeCo 2 P 2 with the c direction as the easy axis.…”

“…The intermediate valence of Ce in this compound was recently directly confirmed by X-ray absorption spectroscopy and resonant inelastic X-ray scattering. [67] The magnetic anisotropy of CeRu 2 P 2 is reversed to CeCo 2 P 2 with the c direction as the easy axis. However, the overall size of the magnetic anisotropy is around 1.5 and therefore similar as observed for CeCo 2 P 2 above T N .…”

Crystal electric field in CeRh2Si2 studied with high-resolution resonant inelastic soft x-ray scattering

“…We have recently shown that these excitations can in principle also be seen with RIXS at the M 4,5 edges of the lanthanides [4] but the available energy resolution of 100 meV and more was simply not sufficient for resolving the CEF splittings in rare earth ions (few tens of meV).…”

Determining the local low-energy excitations in the Kondo semimetalCeRu4Sn6using resonant inelastic x-ray scattering

“…First feasibility experiments have proven its sensitivity to f f excitations. 17,18 Following a second order perturbation treatment, RIXS can be interpreted as the absorption of a photon resonant at a core edge of an ion in the system, followed by a reemission. When the system is left in an excited state, excitation energies are detected as energy losses of the scattered photons.…”

“…31 The spin-orbit interaction in the 4f shell has been reduced by 10 %. 17,18 The calculations were set up for the back-scattering geometry (2θ = 150 • ), grazing incidence (Θ * = 20 • ), and with the tetragonal c-axis (normal to the sample surface) in the scattering plane (see insets in Fig. 2 The calculations in Fig.…”