Vortex lattices and broken time reversal symmetry in the topological superconductor UPt3

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; M. R. Eskildsen

doi:10.1038/s41567-020-0822-z

arXiv · 1812.05690

Vortex lattices and broken time reversal symmetry in the topological superconductor UPt3

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·M. R. Eskildsen

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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 driven non-monotonic vortex lattice rotation, driven by competing effects of 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.

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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, M. R. Eskildsen. 2018-12-13. Vortex lattices and broken time reversal symmetry in the topological superconductor UPt3. https://doi.org/10.1038/s41567-020-0822-z

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