Search

We have performed a high-resolution angle-resolved photoemission spectroscopy (ARPES) on single-crystal ${\mathrm{URu}}_{2}{\mathrm{Si}}_{2}$ to study the band structure and the Fermi surface in the paramagnetic phase. The valence-band structure consisting of the Ru $4d$ and Si $3p$ states shows a qualitatively good agreement between 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 with the band calculation as well as with the de Haas\char21{}van Alphen (dHvA) result suggests that the experimental band near ${E}_{F}$ is assigned to the largest hole pocket centered at the Z point, which has a strong U $5f\ensuremath{-}\mathrm{Ru}4d$ hybridized character. The observed remarkable narrowing of the near-${E}_{F}$ band compared with the band-structure calculation suggests a strong renormalization effect due to the electron correlation of U $5f$ electrons.