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arXiv · 1410.1482

Observation of broken time-reversal symmetry in the heavy fermion superconductor UPt$_3$

E. R. Schemm·W. J. Gannon·C. M. Wishne·W. P. Halperin·A. Kapitulnik
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Abstract

The symmetry properties of the order parameter characterize different phases of unconventional superconductors. In the case of the heavy-fermion superconductor UPt$_3$, a key question is whether its multiple superconducting phases preserve or break time-reversal symmetry (TRS). We tested for asymmetry in the phase shift between left and right circularly polarized light reflected from a single crystal of UPt$_3$ at normal incidence, finding that this so-called polar Kerr effect appears only below the lower of the two zero-field superconducting transition temperatures. Our results provide evidence for broken TRS in the low-temperature superconducting phase of UPt$_3$, implying a complex two-component order parameter for superconductivity in this system.

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E. R. Schemm, W. J. Gannon, C. M. Wishne, W. P. Halperin, A. Kapitulnik. 2014-10-06. Observation of broken time-reversal symmetry in the heavy fermion superconductor UPt$_3$. https://doi.org/10.1126/science.1248552

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