"Evidence for broken time-reversal symmetry in the superconducting phase of URu2Si2 "

E. R. Schemm: R. E. Baumbach, P. H. Tobash, F. Ronning, E. D. Bauer, and A. Kapitulnik; Phys. Rev. B 91, 04/30/15.

Additional Authors: R. E. Baumbach, P. H. Tobash, F. Ronning, E. D. Bauer, and A. Kapitulnik

Abstract:

Recent experimental and theoretical interest in the superconducting phase of the heavy-fermion material URu2Si2 has led to a number of proposals in which the superconducting order parameter breaks time-reversal symmetry (TRS). In this study we measure the polar Kerr effect (PKE) as a function of temperature for several high-quality single crystals of URu2Si2. We find an onset of PKE below the superconducting transition that is consistent with a TRS-breaking order parameter. This effect appears to be independent of an additional, possibly extrinsic, PKE generated above the hidden order transition at THO =17.5 K, and contains a structure below Tc suggestive of additional physics within the superconducting state.