August 15, 2013
Hosted by: Prof. Richard Osgood
Speaker: Dr. Shancai Wang (Professor, Dept. of Physics, Renmin University)
Iron-based superconductors (IBSCs) are a type of unconventional superconductor that cannot be understood in terms of BCS theory because their Tc (up to 55K) exceeds the McMillan limit. Among the four families of the IBSCs, the NaFeAs/LiFeAs family has a nonpolar surface without surface contamination which is ideal for angle-resolved photoemission (ARPES) study of band structure and gap symmetry. In this talk, we will focus on the electronic structure of the cobalt-doped NaFeAs and LiFeAs to understand the mechanism of superconductivity in iron-based superconductors. In both materials, we discovered that the band near Fermi level has a complicated orbital character and that the gap symmetry exhibits s-wave-like symmetry. A possible pairing scenario will be discussed.
Dr. Shancai Wang obtained his Ph.D from Boston College in 2004. He worked as a postdoctoral researcher at Boston University (2004- 2006) and Columbia University (2006-2007) where he studied the electron structure of organic materials and noble metals. In 2007, he joined the faculty of Department of Physics at Renmin University, China. His research fields include strongly correlated system such as conventional superconductivity, organic superconductors, metal-insulator transition systems, surface sciences, and low-dimensional systems.