Direct evidence for electron hole depletion in La0.5Sr0.5FeO3-d upon B-site cation doping

Abstract

Partial substitution of Fe by Ta in the hole-doped La0.5Sr0.5FeO3 decreases the electric conductivity by up to three orders of magnitude. This decrease is in immediate correlation with a decrease of the electron hole concentration and a shift of the spectral weight within the O(1s)-Fe(3d) mixed states from eg bands near the Fermi energy to t2g bands. Corresponding differences in the Fe(2p) and O(1s) X-ray absorption spectra reveals formation of states with increased covalency in the initial state and states which contain O(2p) character, and that hole states are responsible for transport changes in the material. The intensity ratio of eg and t2g bands appears to be a spectral indicator for hole formation.

arXiv commentPACS numbers: 71.27.+a, 71.30.+h, 71.38.-k, 72.10.Fk, 78.70.Dm

References in corpus (3)

• Hole-doping-induced changes in the electronic structure of La${}_{1-x}$Sr${}_x$FeO${}_3$ : soft x-ray photoemission and absorption study of epitaxial thin films
• Disorder effects in electronic structure of substituted transition metal compounds
• Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La${}_{1-x}$Sr${}_x$FeO${}_3$

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• Correlation of conductivity and angle integrated valence band photoemission characteristics in single crystal iron perovskites for 300 K < T < 800 K: Comparison of surface and bulk sensitive methods
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