Evidence for correlation effects in Sr2RuO4 from resonant and x-ray photoemission spectroscopy.

Abstract

We study the electronic structure of Sr{sub 2}RuO{sub 4}, a noncuprate layered superconductor ({ital T}{sub {ital c}}=0.93 K), using electron spectroscopy. X-ray photoemission spectroscopy shows that the single particle occupied density of states (DOS) is in fair agreement with the calculated DOS. However, resonant photoemission spectroscopy across the Ru 4{ital p}-4{ital d} threshold establishes the existence of a correlation satellite to the Ru 4{ital d} band. The results indicate substantial charge-transfer character at the Fermi level, with on-site correlations {ital U}{sub {ital dd}} comparable in magnitude to the Ru-O hopping integral, like the cuprates. {copyright} {ital 1996 The American Physical Society.}