报告摘要：We apply the functional renormalization group method to study the pairing symmetry and pairing mechanism of the iron-based superconductors. Based on a five-band model and local repulsive interactions we find an electronic-interaction-driven pairing instability. For the parameter range we have studied the strongest pairing channel is always the extended-s-wave, whose order parameter has opposite signs on electron and hole Fermi surfaces. The pairing mechanism is the Cooper scattering between electron and hole Fermi surfaces, driven by antiferromagnetic interactions.

报告人简介：Dr. Wang Fa received his B.S. degree in Physics from Peking University in 2004. He received his Ph.D. in Physics from UC Berkeley in 2009. He will join the Physics department of MIT as a Pappalardo Fellow this fall. His research interests include studying correlated electron systems where unconventional phases of matter and phase transitions can be realized, understanding the role of electron interactions in the high temperature superconductivity, mainly in the context of the iron-base high-Tc, etc.