Principal Investigator Nuh Gedik
Superconductivity is the result of the resistanceless flow of paired electrons known as Cooper pairs. In conventional materials, such as pure metals and alloys, the cause of this phenomenon is well known: a distortion of the lattice, produced by the passage of one electron, serves to attract a second electron in its wake. By contrast, the mechanism of high temperature superconductivity, exhibited separately by the copper oxide and iron pnictide superconductors, has yet to be successfully understood. What binds these electrons together? Are copper oxide and iron pnictide superconductivity related? How do the various other forms of electronic order exhibited by both classes, such as antiferromagnetism in the cuprates and spin-density wave order in the pnictides, impact superconductivity?
We have been attempting to address these fundamental questions using the powerful methods of ultrafast time-resolved spectroscopies. In these measurements, we break the Cooper pair apart using a femtosecond laser pulse. By watching the dynamics of these particles in real time as they relax and recreate their original ordered state, we can learn about how these charge carriers organize themselves within the solid, gain insight into what glues them together into Cooper pairs, and how superconductivity interacts with the other coexisting forms of order.