Aharon Kapitulnik , Stanford University
Search for Broken Time-reversal Symmetry States
in Novel Superconductors

Until recently, broken time reversal symmetry breaking (TRSB) states in solids could be found exclusively in magnetic systems. However, the discovery of high temperature superconductors brought forward the possibility that with unconventional superconductivity, also new states of broken time reversal symmetry are possible. In this talk I will review the search for broken time reversal symmetry in novel superconductors, starting from the quest for anyon superconductivity, the discovery of TRSB state in strontium-ruthenate Sr2RuO4 and the revived search of TRSB state in high temperature superconductors. I will particularly highlight the experimental difficulty in measuring TRSB effects and the invention of the "Sagnac magnetometer" that enabled our recent discoveries.

References:

1. Jing Xia, Yoshiteru Maeno, Peter T. Beyersdorf, M.M. Fejer, and A.
Kapitulnik, Phys. Rev. Lett 97, 167002 (2006)

2. Charles Day "Superconductor forms domains that break time-reversal symmetry", Physics Today, (Search and Discovery), December 2006, p. 23