期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2009
卷号：106
期号：18
页码：7330-7333
DOI：10.1073/pnas.0900469106
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The discovery of high-temperature superconductivity in iron pnictides 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 Ba0.6K0.4Fe2As2, the pairing strength is enhanced simultaneously (2{Delta}/Tc{approx}7) on the nearly nested FS pockets, i.e., the inner hole-like ({alpha}) FS and the 2 hybridized electron-like FSs, whereas the pairing remains weak (2{Delta}/Tc{approx}3.6) in the poorly nested outer hole-like ({beta}) FS. Here, we report that in the electron-doped BaFe1.85Co0.15As2, the FS nesting condition switches from the {alpha} to the {beta} FS due to the opposite size changes for hole- and electron-like FSs upon electron doping. The strong pairing strength (2{Delta}/Tc{approx}6) is also found to switch to the nested {beta} FS, indicating an intimate connection between FS nesting and superconducting pairing, and strongly supporting the inter-FS pairing mechanism in the iron-based superconductors.
关键词：angle-resolved photoemission ; band structure ; iron pnictide ; superconductivity
