Pairing Symmetry and Multiple Energy Gaps in Multi-Orbital Iron-Pnictide Superconductors

摘要: Since the new high-Tc superconducting family based on iron pnictides was discovered Kamihara et al. (2008); Chen (2008a;b), and critical temperature lifted to 56 K under high pressure Wu (2009) which is considerably larger than McMillan Limit (1968), superconductive pairing mechanism properties have attracted great interests experimentally theoretically. These newly-found superconductors also provide a potential application prospect in two respects: one hand, simple components rich resource of FeAs-based compounds show most possibility large-scale applications; other extremely large upper fields Hc2Wen (2008) FeAs imply realistic applications near future. To find higher Tc further experiments improve their currrent density, it essentially important theoretically understand various normal pnictides, especially symmetry its microscopic mechanism. Once known, many could be qualitatively understood.