Seminars & Colloquia

Vorticity and the phase diagram of high temperature superconductors, revisited

N. Phuan Ong
Physics Department,
Princeton University
30 April 4:00 pm Higgins 310

The flow of vortices in a superconductor engenders a weak Josephson electric field that may be detected in a Nernst experiment. We have used this tool as a detector of vorticity over a large swath of the field-temperature-doping phase diagram in several families of the cuprates. We show that the pairing amplitude is actually non-zero above the 'transition temperature' Tc0. Measurements of the upper critical field over most of the phase diagram reveal a pairing strength much larger than previously suspected. The results paint a picture that is pointedly at odds with many entrenched scenarios and theories, while supporting a remaining few. A progress report of current work on superconducting cobalt oxides will also be given.