Quest for new superconductors, or superconductivity entering the Iron Age

Tuesday, October 2, 2012 - 3:15pm - 4:15pm
Reiss 502
Igor Mazin
Naval Research Laboratory

First, I will tell the story, partially based on personal reminiscences, about the early days of superconductivity (up to the late 80s), when theorists were debating whether there was a fundamental limit for the superconducting temperature. Many prominent scientists argued (incorrectly) that such a limit existed, while the other school, led by V.L. Ginzburg, disagreed. The latter turned out to be right, however, it appeared that physicists, including Ginzburg himself, never looked for high-Tc superconductors in the right place. A set of recipes, known as Matthias riles after a great material scientist of the time, were generally accepted, but appeared to be very wrong. One, and then another system were found literally in the opposite corner of the room (Cu- and Fe-based superconductors). Again two schools of thoughts emerged, now centered around the concept of a “pairing glue”, in other words, whether the new superconductors can be construed as unconventional generalizations of the conventional Bardeen-Cooper-Schriffer theory, or represent a qualitatively new physics. In my talk I will adopt the former view and will present a new, “iron age” set of rules that hopefully could lead to further discoveries in the quest for new superconductors.