The atomic dynamics of the guest modes in heavy fermion filled skutterudites ROs 4Sb 12 were investigated by inelastic x-ray scattering. Comparison of the phonon dispersion relations for the filled skutterudite SmOs 4Sb 12 with those for the unfilled skutterudite IrSb 3 indicates that the guest modes in filled skutterudites are observed as additional modes in the unfilled skutterudites. The dispersion relations for IrSb 3 and SmOs 4Sb 12 agree reasonably well with the results obtained by ab initio calculations for IrSb 3 and LaOs 4Sb 12, respectively. The rare-earth dependence of the inelastic x-ray scattering spectrum in the series of ROs 4Sb 12 compounds is difficult to interpret in terms of changes in the atomic mass and electron number of the rare-earth atom inserted into the Sb cage. The combination of inelastic x-ray scattering and x-ray absorption spectroscopy reveals a correlation between the guest mode energy and the guest free space in these compounds. The rare-earth dependence of the inelastic x-ray scattering spectrum indicates the mediation of heavy fermion behavior by the atomic motion of the guest in some ROs 4Sb 12 compounds and the electron-phonon coupling between the guest modes with 4f-electrons and conduction electrons in the series of ROs 4Sb 12 compounds.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2012 Nov 12|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics