Electronic Structure and Electron Correlation in LaFeAsO1-xFx and LaFePO1-xFx

Photoemission spectroscopy is used to investigate the electronic structure of the newly discovered iron-based superconductors LaFeAsO 1- x F x and LaFePO 1- x F x . Line shapes of the Fe 2 p core-level spectra suggest an itinerant character of Fe 3 d electrons. The valence-band spectra are generally consistent with band-structure calculations except for the shifts of Fe 3 d -derived peaks toward the Fermi level. From the spectra taken in the Fe 3 p → 3 d core-absorption region, we have obtained the experimental Fe 3 d partial density of states, and explained it in terms of a band-structure calculation with a phenomenological self-energy correction, yielding a mass renormalization factor of \({\lesssim}2\).