Band structure ofUPd3studied by ultrahigh-resolution angle-resolved photoemission spectroscopy

Abstract

We have performed ultrahigh-resolution angle-resolved photoemission spectroscopy on ${\mathrm{UPd}}_{3}$ 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 $\mathit{\ensuremath{\Gamma}}$ (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 ${\mathrm{UPd}}_{3}.$