Band structure and Fermi surface of URu2Si2 studied by high-resolution angle-resolved photoemission spectroscopy

We have performed a high-resolution angle-resolved photoemission spectrosco py (ARPES) on single-crystal URu2Si2 to study the band structure and the Fe rmi surface in the paramagnetic phase. The valence-band structure consistin g of the Ru 4d and Si 3p states shows a qualitatively good agreement betwee n the ARPES experiment and the band-structure calculation, In the vicinity of the Fermi level (E-F) we observed a less dispersive band, which crosses E-F midway between the Z and X points in the Brillouin zone. Comparison wit h the band calculation as well as with the de Haas-van Alphen (dHvA) result suggests that the experimental band near E-F is assigned to the largest ho le pocket centered at the Z point, which has a strong U Sf-Ru 4d hybridized character. The observed remarkable narrowing of the near-E-F band compared with the bandstructure calculation suggests a strong renormalization effec t due to the electron correlation of U 5f electrons, [S0163-1829(99)01343-0 ].