Bulk-sensitive photoemission spectroscopy for heavy-fermion Pr compounds using hard x-ray

Bulk-sensitive photoemission spectroscopy using hard x-ray up to h nu = 5450 eV has been performed for heavy-fermion Pr compounds. A significant spectral intensity of the |3(9)4f(3)> final state was observed in Pr 3d core-level spectra of PrFe4P12 at both h nu = 2450 and 5450 eV. The spectra obtained by the configuration-interaction cluster model calculation reproduce the experimental spectra for well-hybridized PrFe4P1, and localized Pr metal. Results of the calculations suggest that the Kondo behavior observed in PrFe4P12 arise from the mixing of the |4f(2)> and |4f(3)> configurations due to the c-f hybridization. Whereas a contribution possibly from a disordered surface to the spectrum can be the fractured PrFe4P12, they cannot be disregarded for the scraped PrSn3 and Pr metal even negligible for the in the high-energy x-ray region.