Band structure of UPd₃ studied by ultrahigh-resolution angle-resolved photoemission spectroscopy

We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy on UPd₃ to study the band structure near the Fermi level (E_F) and the Fermi surface. We found three Fermi surfaces (FS's): two hole pockets with a dominant Pd 4d character at the Γ (A) point and an electron pocket with a U 6d nature at the K (H) point. These FS's are qualitatively well reproduced in the band structure calculation based on the localized U-5f-electron model, while remarkable quantitative discrepancies are observed near E_F. The U 5f states are located 0.4-1.0 eV below E_F and do not contribute to the Fermi surface. These results indicate the strongly localized nature of U 5f electrons in UPd₃.