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Autori: Byron Freelon, Yi-sheng Liu, Costel R. Rotundu, Stephen D. Wilson, Jinghua Guo, Jeng-Lung Chen, Wanli Yang, Chunli Chang, Per Anders Glans, Parasharam Shirage, Akira Iyo, and Robert J. Birgeneau
Editorial: The Physical Society of Japan, Journal of the Physical Society of Japan, 79, p.074716, 2010.
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-d has weak to intermediate electron correlations.
Cuvinte cheie: electron correlations, electronic density of states, high-temperature superconductors, iron arsenide compounds, lanthanide compounds, x-ray emission spectra, x-ray absorption spectra, superconducting transitions, valence bands