Important aspects related to the pairing mechanism of iron-based superconductors revealed by ARPES
Beijing National Laboratory for Condensed Matter Physics, and Institute of Physics, Chinese Academy of Sciences
The recent discovery of superconductivity in iron-arsenic compounds with a transition temperature (Tc) as high as 55 K ended the monopoly of copper oxides in the family of high-Tc superconductors. In this talk I will report our angle-resolved photoelectron spectroscopy (ARPES) results on many pnictides, including discoveries of Fermi-surface-dependent nodeless superconducting gaps, a low-energy dispersion kink with signature of an AF spin resonance mode, and the evolution of Fermi surface and superconducting gaps as different doping levels. Our comprehensive ARPES results have revealed the nature of extended s-wave pairing, and strongly suggested the inter-FS scattering over nearly nested electron-hole FS pockets as the main driving force for the superconductivity of this new class of high- Tc superconductors.