Self-energy on the low- to high-energy electronic structure of correlated metal SrVO ₃

The correlated electronic structure of SrVO ₃ has been investigated by angle-resolved photoemission spectroscopy using insitu prepared thin films. Pronounced features of band renormalization have been observed: a sharp kink ∼60meV below the Fermi level (E _F) and a broad so-called "high-energy kink" ∼0.3eV below E _F as in the high-T _c cuprates, although SrVO ₃ does not show magnetic fluctuations. We have deduced the self-energy in a wide energy range by applying the Kramers-Kronig relation to the observed spectra. The obtained self-energy clearly shows a large energy scale of ∼0.7eV, which is attributed to electron-electron interaction and gives rise to the ∼0.3eV kink in the band dispersion as well as the incoherent peak ∼1.5eV below E _F. The present analysis enables us to obtain a consistent picture for both the incoherent spectra and the band renormalization.