KIAS workshop "From correlated electrons to nanoscale materials"

at Korea Institute for Advanced Study (KIAS), Seoul, Korea

• Yunkyu Bang
  
  Chonnam National University
  
  

  Title

  New High-Tc Superconductor: Fe-based Oxypnictides

  Abstract

  I will start with a brief overview of the experimental status about the recently discovered Fe-based SC. With a theoretical analysis, we propose the sign-changing S-wave gap is the most promising gap symmetry of this new high-Tc SC. Switching gears, I will discuss contradicting experimental observations in NMR and penetration depth measurements which shows a SC state with lines of node and a fully opened gap, respectively. I will show an important role of resonant impurity scattering in the sign-changing S-wave gap and how to explain the experimental puzzles with it. Finally I will discuss a possible common thread of pairing mechanism from the HTSC cupurates (Tc~100K) , Fe-based SC (Tc~ 50K), Pu-115 SC (Tc~ 20K) and various heavy fermion SC (Tc < 1 K).