Valence-band and core-level photoemission spectroscopy ofLaFeAsO1−xFx

We have investigated the electronic structure of ${\text{LaFeAsO}}_{1-x}{\text{F}}_x$ $\left(x=0;0.1;0.2\right)$ by angle-integrated photoemission spectroscopy and local-density approximation (LDA)-based band-structure calculations. The valence band consists of a low-energy peak at $E\approx -0.25\text{eV}$ and a broad structure around $E\approx -5\text{eV}$, which are in qualitative agreement with LDA. From the photon-energy dependence of these peaks we conclude that the former derives almost exclusively from $\text{Fe}3d$ states. This constitutes experimental evidence for the strong iron character of the relevant states in a broad window around $E_F$ and confirms theoretical predictions.