Optical conductivity of CePd 3, YPd 3 and PrPd 3

Abstract

The optical conductivity of intermediate valence CePd 3 at 300 K exhibits a maximum near 16 meV, which is absent in the reference materials YPd 3 and PrPd 3. Using a modified Drude model with a memory function ansatz this anomaly has been identified as a resonant electron-electron scattering process of conduction electrons at the localized 4f states near the Fermi level E F. The model fit gives estimates of the width of the 4f states, of their separation from E F and of the f-d hybridization energy. Intra-4f transitions of CePd 3 are stronger compared to those of PrPd 3 due to the stronger f-d hybirdization. 4d→4f transition energies of CePd 3 are reduced due to an electron-hole Coulomb binding energy.