Kondo Takeshi, Santander-Syro A F, Copie O, Liu Chang, Tillman M E, Mun E D, Schmalian J, Bud'ko S L, Tanatar M A, Canfield P C, Kaminski A
Ames Laboratory and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011, USA.
Phys Rev Lett. 2008 Oct 3;101(14):147003. doi: 10.1103/PhysRevLett.101.147003. Epub 2008 Oct 2.
We use angle resolved photoemission spectroscopy to study the momentum dependence of the superconducting gap in NdFeAsO0.9F0.1 single crystals. We find that the Gamma hole pocket is fully gapped below the superconducting transition temperature. The value of the superconducting gap is 15+/-1.5 meV and its anisotropy around the hole pocket is smaller than 20% of this value-consistent with an isotropic or anisotropic s-wave symmetry of the order parameter. This is a significant departure from the situation in the cuprates, pointing to the possibility that the superconductivity in the iron arsenic based system arises from a different mechanism.
我们使用角分辨光电子能谱来研究NdFeAsO0.9F0.1单晶中超导能隙的动量依赖性。我们发现，在超导转变温度以下，Γ空穴口袋完全能隙化。超导能隙的值为15±1.5毫电子伏特，其在空穴口袋周围的各向异性小于该值的20%——这与序参量的各向同性或各向异性s波对称性一致。这与铜酸盐的情况有显著不同，表明铁砷基体系中的超导性可能源于不同的机制。
