Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La$_{1-x}$Sr$_x$FeO$_3$

H. Wadati; A. Chikamatsu; R. Hashimoto; M. Takizawa; H. Kumigashira; A. Fujimori; M. Oshima; M. Lippmaa; M. Kawasaki; H. Koinuma

doi:10.1143/JPSJ.75.054704

paper

Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La $_{1 - x}$ Sr $_{x}$ FeO $_{3}$

arXiv:cond-mat/0410202 · doi:10.1143/JPSJ.75.054704

Abstract

We have measured the temperature dependence of the photoemission and x-ray absorption spectra of La $_{1 - x}$ Sr $_{x}$ FeO $_{3}$ (LSFO) epitaxial thin films with $x = 0.67$ , where charge disproportionation ( $3 F e^{3.67 +} \to 2 F e^{3 +} + F e^{5 +}$ ) resulting in long-range spin and charge ordering is known to occur below $T_{C D} = 190$ K. With decreasing temperature we observed gradual changes of the spectra with spectral weight transfer over a wide energy range of $\sim 5$ eV. Above $T_{C D}$ the intensity at the Fermi level ( $E_{F}$ ) was relatively high compared to that below $T_{C D}$ but still much lower than that in conventional metals. We also found a similar temperature dependence for $x = 0.4$ , and to a lesser extent for $x = 0.2$ . These observations suggest that a local charge disproportionation occurs not only in the $x = 0.67$ sample below $T_{C D}$ but also over a wider temperature and composition range in LSFO. This implies that the tendency toward charge disproportionation may be the origin of the unusually wide insulating region of the LSFO phase diagram.

6 pages, 8 figures

Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La $_{1 - x}$ Sr $_{x}$ FeO $_{3}$

Abstract

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Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La1−x​Srx​FeO3​

Abstract

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Cited by in corpus (4)

Temperature-dependent soft x-ray photoemission and absorption studies of charge disproportionation in La $_{1 - x}$ Sr $_{x}$ FeO $_{3}$