Qimiao Si
Department of Physics and Astronomy, Center for Quantum Materials, Rice University
Abstract:
Strongly correlated electron systems often feature multiple building blocks and competing interactions, which allow for plenty of surprises and ample opportunities for new physics. An important case study is provided by the iron-based superconductors, which have been the subject of extensive efforts during the past decade or so.
In this overview talk, I will survey some of the key issues about the physics of the iron-based superconductors and the progress that has been made in their understanding. For the normal state, the questions concern the degree of electron correlations and, relatedly, the electronic (magnetic and nematic) orders and their fluctuations. For the superconducting state, these include the amplitude and structure of the multiorbital superconducting pairing. Among the overarching themes are the role of bad metallicity, magnetic fluctuations, quantum criticality and orbital selectivity. I will close by touching upon the prospect for future advances in resolving some of the problems that remain outstanding.