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

Research output: Contribution to journalArticle

3 Citations (Scopus)

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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Photoelectron spectroscopy
Superconducting transition temperature
Electronic structure
photoelectric emission
electronic structure
orbitals
Fermi surface
Electrons
Fermi level
transition temperature
spectroscopy
Doping (additives)
Fermi surfaces
electrons

Keywords

  • ARPES
  • Excitonic insulator
  • FeAs layer
  • Orbital degeneracy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

Cite this

Electronic structure of BaFe 2-x Co x As 2 revealed by angle-resolved photoemission spectroscopy. / Mizokawa, Takashi; Sudayama, T.; Wakisaka, Y.; Morinaga, R.; Sato, T. J.; Arita, M.; Namatame, H.; Taniguchi, M.; Saini, N. L.

In: Journal of Superconductivity and Novel Magnetism, Vol. 24, No. 3, 04.2011, p. 1133-1136.

Research output: Contribution to journalArticle

Mizokawa, T, Sudayama, T, Wakisaka, Y, Morinaga, R, Sato, TJ, Arita, M, Namatame, H, Taniguchi, M & Saini, NL 2011, 'Electronic structure of BaFe 2-x Co x As 2 revealed by angle-resolved photoemission spectroscopy', Journal of Superconductivity and Novel Magnetism, vol. 24, no. 3, pp. 1133-1136. https://doi.org/10.1007/s10948-010-1095-z
Mizokawa, Takashi ; Sudayama, T. ; Wakisaka, Y. ; Morinaga, R. ; Sato, T. J. ; Arita, M. ; Namatame, H. ; Taniguchi, M. ; Saini, N. L. / Electronic structure of BaFe 2-x Co x As 2 revealed by angle-resolved photoemission spectroscopy. In: Journal of Superconductivity and Novel Magnetism. 2011 ; Vol. 24, No. 3. pp. 1133-1136.
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AU - Sato, T. J.

AU - Arita, M.

AU - Namatame, H.

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N2 - 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.

AB - 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.

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