TY - JOUR
T1 - Fermi surface nesting induced strong pairing in iron-based superconductors
AU - Terashima, K.
AU - Sekiba, Y.
AU - Bowen, J. H.
AU - Nakayama, K.
AU - Kawahara, T.
AU - Sato, T.
AU - Richard, P.
AU - Xu, Y. M.
AU - Li, L. J.
AU - Cao, G. H.
AU - Xu, Z. A.
AU - Ding, H.
AU - Takahashi, T.
PY - 2009/5/5
Y1 - 2009/5/5
N2 - 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.
AB - 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.
KW - Angle-resolved photoemission
KW - Band structure
KW - Iron pnictide superconductivity
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U2 - 10.1073/pnas.0900469106
DO - 10.1073/pnas.0900469106
M3 - Article
C2 - 19359490
AN - SCOPUS:66249134598
SN - 0027-8424
VL - 106
SP - 7330
EP - 7333
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 18
ER -