CMT158

Broken time reversal symmetry in the topological superconductor UPt₃

• Author(s): K. E. Avers, W. J. Gannon, S. J. Kuhn, W. P. Halperin, J. A. Sauls, L. DeBeer-Schmitt, C. D. Dewhurst, J. Gavilano, G. Nagy, U. Gasser, and M. R. Eskildsen
• Address: Center for Applied Physics & Superconducting Technologies, Northwestern University, Evanston, IL 60208
• Date: December 13, 2018
• Journal: Nature Physics, 16, 531-535 (2020) [DOI] [SharedIt]
• Abstract: The topological superconductor UPt₃, has three distinct vortex phases, a strong indication of its unconventional character. Using small-angle neutron scattering we have probed the vortex lattice in the UPt₃ B phase with the magnetic field along the crystal c-axis. We find a difference in the vortex lattice configuration depending on the sign of the magnetic field relative to the field direction established upon entering the B phase at low temperature in a field sweep, showing that the vortices in this material posses an internal degree of freedom. This observation is facilitated by the discovery of a field dependent non-monotonic vortex lattice rotation, driven by competing effects due to the superconducting gap distortion and the vortex-core structure. From our bulk measurements we infer that the superconducting order parameter in the UPt₃ B phase breaks time reversal symmetry and exhibits chiral symmetry with respect to the c-axis.

• Comment: 5 pages, 6 figures, Supplementary Material

• Eprint: [PDF] [arXiv]

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