Fermi surface nesting induced strong pairing in iron-based superconductors

K. Terashima, Y. Sekiba, J. H. Bowen, K. Nakayama, T. Kawahara, T. Sato, P. Richard, Y. M. Xu, L. J. Li, G. H. Cao, Z. A. Xu, H. Ding, T. Takahashi

Research output: Contribution to journalArticlepeer-review

290 Citations (Scopus)

Abstract

The discovery of high-temperature superconductivity in iron pnic- tides raised the possibility of an unconventional superconducting mechanism in multiband materials. The observation of Fermi- surface (FS)-dependent nodeless superconducting gaps suggested that inter-FS interactions may play a crucial role in superconducting pairing. In the optimally hole-doped Ba 0.6K 0.4Fe 2As 2, the pairing strength is enhanced simultaneously (2Δ/T c≈7) on the nearly nested FS pockets, i.e., the inner hole-like (a) FS and the 2 hybridized electron-like FSs, whereas the pairing remains weak (2Δ/T c≈3.6) in the poorly nested outer hole-like (β) FS. Here, we report that in the electron-doped BaFe 1.85Co 0.15As 2, the FS nesting condition switches from the α to the β FS due to the opposite size changes for hole- and electron-like FSs upon electron doping. The strong pairing strength (2Δ/T c≈6) is also found to switch to the nested β FS, indicating an intimate connection between FS nesting and superconducting pairing, and strongly supporting the inter-FS pairing mechanism in the iron-based superconductors.

Original languageEnglish
Pages (from-to)7330-7333
Number of pages4
JournalProceedings of the National Academy of Sciences of the United States of America
Volume106
Issue number18
DOIs
Publication statusPublished - May 5 2009

Keywords

  • Angle-resolved photoemission
  • Band structure
  • Iron pnictide superconductivity

ASJC Scopus subject areas

  • General

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