X-ray Absorption and Emission Spectroscopy Study of the Effect of Doping on the Low Energy Electronic Structure of PrFeAsO1-δ

Abstract

We report electronic density of states measurements of oxygen vacated PrFeAsO using soft X-ray absorption and emission spectroscopy. The electronic density of states is observed to undergo doping dependent shifts. Oxygen X-ray absorption and emission show long-range intermixing of oxygen p states. Mean field theory and local density approximations give a good description of the measured oxygen and iron spectra. The near Fermi-level iron spectral weight shows a systematic doping dependence. Concomitant changes in the unoccupied iron-arsenic hybridized spectral features reveal that Fe-As bonding is involved in the process of electron addition near the Fermi-level. By combining x-ray emission and absorption spectra, we observe an increase in the Fe density of states at the Fermi-level as the doping decreases. This doping dependent electronic behavior indicates the possibility of a magnetic instability in the undoped compound. Our data overall imply that PrFeAsO1� � has weak to intermediate electron correlations.