Electronic structure of BaFe 2-x Co x As 2 revealed by angle-resolved photoemission spectroscopy

Takashi Mizokawa, T. Sudayama, Y. Wakisaka, R. Morinaga, T. J. Sato, M. Arita, H. Namatame, M. Taniguchi, N. L. Saini

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Abstract

We report an angle-resolved photoemission spectroscopy study of BaFe 2-x Co x As 2. For x=0, above the structural and magnetic transition temperature (T s ), the spectral weight near the Fermi level is considerably suppressed around the Γ point where the Fe 3d yz/zx orbital degeneracy is expected. This observation suggests that the Jahn-Teller type instability is playing an important role in the tetragonal phase above T s . Below T s, the spectral weight of 0-100 meV is reconstructed to form flat bands at 70-100 meV and Fermi surfaces, consistent with the orbital-dependent excitonic coupling. In the optimally doped and overdoped regimes, the hole pocket around the Γ point and the electron pocket around the M point are apparently nested, indicating that the doping dependence of the superconducting transition temperature cannot be explained by the nesting scenario and that the unusual electron-lattice fluctuation due to the orbital degeneracy is important.

Original languageEnglish
Pages (from-to)1133-1136
Number of pages4
JournalJournal of Superconductivity and Novel Magnetism
Volume24
Issue number3
DOIs
Publication statusPublished - 2011 Apr
Externally publishedYes

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Keywords

  • ARPES
  • Excitonic insulator
  • FeAs layer
  • Orbital degeneracy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Mizokawa, T., Sudayama, T., Wakisaka, Y., Morinaga, R., Sato, T. J., Arita, M., Namatame, H., Taniguchi, M., & Saini, N. L. (2011). Electronic structure of BaFe 2-x Co x As 2 revealed by angle-resolved photoemission spectroscopy. Journal of Superconductivity and Novel Magnetism, 24(3), 1133-1136. https://doi.org/10.1007/s10948-010-1095-z