Angular dependence of x-ray absorption spectrum for field-aligned iron-based superconductors

B. C. Chang, Y. B. You, T. J. Shiu, M. F. Tai, H. C. Ku, Y. Y. Hsu, L. Y. Jang, J. F. Lee, Z. Wei, K. Q. Ruan, X. G. Li

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17 Citations (Scopus)


Anisotropic FeK -edge and AsK -edge x-ray absorption near-edge spectrum measurements on superconducting (Tc =52 K) (Sm0.95 La0.05) FeAs (O0.85 F0.15) field-aligned microcrystalline powder are presented. The angular dependence of Fe pre-edge peak (dipole transition of Fe1s electrons to Fe3d/As4p hybrid bands) relative to the tetragonal ab plane of aligned powder indicates larger density of state along the c axis and is consistent with the local-density approximation band-structure calculation. The anisotropic FeK -edge spectra exhibit a chemical shift to lower energy compared to FeO which are closely related to the itinerant character of Fe2+ 3 d6 orbitals. The anisotropic AsK -edge spectra are more or less the mirror images of FeK edge due to the symmetrical Fe-As hybridization in the FeAs layer. Angular dependence of As main peak (dipole transition of As1s electrons to higher-energy hybrid bands) was observed suggesting character of As4d eg orbitals.

Original languageEnglish
Article number165108
JournalPhysical Review B - Condensed Matter and Materials Physics
Issue number16
Publication statusPublished - 2009 Oct 5

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics


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