Manifestation of electron correlation effect in 5 states of uranium compounds revealed by 4-5 resonant photoelectron spectroscopy

Fujimori, Shinichi   ; Kobata, Masaaki  ; Takeda, Yukiharu   ; Okane, Tetsuo  ; Saito, Yuji  ; Fujimori, Atsushi; Yamagami, Hiroshi; Haga, Yoshinori   ; Yamamoto, Etsuji  ; Onuki, Yoshichika*

In the present study, we have elucidated the nature of the electron correlation effect in uranium compounds by imaging the partial density of states (pDOS) of typical itinerant, localized, and heavy fermion uranium compounds by using the 4-5 resonant photoemission spectroscopy. Obtained pDOS exhibit a systematic trend depending on the physical properties of compounds: Although the coherent peak at the Fermi level can be explained by the band-structure calculation, an incoherent peak emerges on the higher binding energy side () in the cases of localized and heavy fermion compounds. The intensity and energy position of the incoherent peak is increased and shifted to a higher binding energy as the localization of the state increases. These behaviors are consistent with the prediction of the Mott metal-insulator transition, suggesting that the Hubbard- type mechanism takes an essential role in the electronic structure of actinide materials.