Physics @ Berkeley
Events in Physics
Title: The Search For Complex Order Parameter Symmetry In Unconventional Superconductors    (Colloquia)
Start Date: 10/13/2008
Time: 4:30 pm
Location: 1 LeConte
Speaker: Dale Van Harlingen
Affiliation: University of Illinois at Urbana Champaign

The discovery of the high-temperature superconductors in the 1980s revealed the existence of materials suspected to have unconventional pairing symmetry characterized by anisotropies in the magnitude and/or phase of the order parameter, in sharp contrast to conventional BCS superconductors.  In this talk, I will describe the technique of Josephson interferometry and review how it was implemented to verify that the high temperature cuprates had a dx2-y2 pairing symmetry.  I will then describe our ongoing quest to identify superconductors with complex order parameters that exhibit broken time-reversal symmetry, focusing on the ruthenate superconductor Sr2RuO4 which is suspected to exhibit a chiral p-wave order parameter of the form pxipy, and on the heavy fermion superconductor UPt3 which exhibits two distinct superconductor phases.  In addition to exhibiting exciting new physics, complex superconductors have potential application for topologically-protected quantum computing.