Pairing symmetry of iron-based superconductors revealed by ARPES
报告人:
丁洪
中国科学院物理研究所 研究员
报告时间:
2008-10-20 14:00
报告地点:
物理系三楼报告厅
主办单位:
物理系
简介:
报告摘要：The recent discovery of superconductivity in iron-arsenic compounds with a transition temperature (Tc ) as high as 56 K ended the monopoly of copper oxides in the family of high-Tc superconductors. In this talk I will report our angle-resolved photoemission (ARPES) observation of the superconducting gap, including its momentum, temperature, and Fermi surface (FS) dependence in single crystals Ba0.6K0.4Fe2As2 (Tc = 37 K). We found two nodeless and nearly isotropic superconducting gaps around their respective FS sheets: a large gap (Δ ~ 12 meV) on the two small hole-like and electron-like FS sheets, and a small gap (~ 6 meV) on the large hole-like FS. The isotropic pairing interactions are strongly orbital dependent, as the ratio 2∆/kBTc switches from weak to strong coupling on different bands. In addition, we have observed a dispersion kink that is likely related to a spin mode. These results reveal the importance of inter-band interactions in the pairing mechanism, and support the anti-phase s-wave pairing symmetry in the Fe-based superconductors.
