A sign of change: pinning down the pairing symmetry of the iron-based superconductors |
| TYPE | Condensed Matter Seminar |
| Speaker: | Erez Berg |
| Affiliation: | Harvard |
| Organizer: | M. Reznikov |
| Date: | 21.12.2010 |
| Time: | 14:30 |
| Location: | Lidow Nathan Rosen (300) |
| Remark: | Candidate for a faculty position |
| Abstract: | The iron-based superconductors, discovered a couple of years ago, hold a great promise, from both a technological and a scientific point of view. With an unusually high maximum critical temperature exceeding 50K, second only to that of the so-called copper-oxide high-temperature superconductors, they are likely to belong to a class of "unconventional" superconductors, whose mechanism lies beyond the Bardeen-Cooper-Schrieffer theory of phonon-mediated pairing. A crucial step to unveil the mechanism of superconductivity in these materials is to understand the structure of their order parameter. In this talk, I will discuss theoretical investigations of the iron-based superconductors, which indicate an exotic order parameter with an internal sign change. Experimentally, detecting such a sign change poses a significant challenge. I will show how a recent intriguing experiment, which shows fractional flux quantization in a composite superconducting loop, can be intepreted as evidence for a sign-changing order parameter. |