Magnetism, Bad Metals and Superconductivity: Iron Pnictides and Beyond

Coordinators: Piers Coleman, Peter Hirschfeld, Srinivas Raghu, Qimiao Si

Scientific Advisors: J.C. Davis, H. Ding, G.G. Lonzarich

The surprising discovery of high-temperature superconductivity in the iron pnictides in 2008 opened up a new avenue of research in condensed matter physics. The intense activity that ensued raised the superconducting transition temperatures in these and related iron-based systems to over 50K, and led to considerable progress towards the understanding of these materials. Many theoretical ideas and approaches have been pursued, bringing major insights into the bad-metal behavior, magnetism, and their remarkable interplay with unconventional superconductivity. A persistent debate is whether the weak-coupling or strong-coupling limit is better suited to describe the microscopic physics. The metallic nature of the iron pnictides has sometimes been taken as evidence for weak coupling, but many of the newer iron-based superconductors show clear signatures for strong correlations. These developments suggest that the time is ripe for a new theoretical attack on the problem of unconventional superconductivity,  one that draws on the commonalities and differences between the iron systems and other unconventional superconductors, including cuprate, heavy-fermion and organic superconductors.

This program will bring together the correlated-electron communities to discuss mechanisms for unconventional superconductivity and  the physics of their unusual normal states. While the inspiration of the program will draw on iron based superconductivity, it will also seek to create new perspectives and a synergy of ideas  by comparing and contrasting the iron systems with their cuprate, organic, rare earth and actinide counterparts.  The program will also  bring together theorists of various perspectives with key experimentalists at the forefront of the field.  It is hoped that crosstalk among these sub-communities will nucleate exciting and new collaborations.