Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session K13: Sr2RuO4 and Chiral Topological Superconductivity
8:00 AM–10:48 AM,
Wednesday, March 7, 2018
LACC Room: 304A
Sponsoring Unit: DMP
Chair: Timo Hyart, Univ of Jyvaskyla
Abstract: K13.00009 : Topology and symmetry in multiple superconducting phases of U1-xThxBe13
10:00 AM–10:12 AM
We theoretically investigate the topological aspect of the multiple superconducting phases in the heavy-fermion compound U1-xThxBe13. The gap symmetry and the multiple phase transitions in this superconductor (SC) have been longstanding unsolved issues. Recent measurements with high-quality single crystals suggests the odd-parity Eu state as a possible scenario [Y. Shimizu et al., arXiv:1709.00128]. In this scenario, the multiple superconducting phases are composed of uniaxial nematic, biaxial nematic, and nonunitary cyclic phases, corresponding to the DIII topological SC, Dirac SC, and Weyl SC, respectively. In this talk, we show that all the phases are accompanied by different types of topological quasiparticles: surface helical Majorana fermions in nematic phases and itinerant Majorana fermions in the cyclic phase. In particular, in the cyclic phase, surface states evoluve from a Majorana cone to Majorana arcs under rotation of surface orientation. The cone is protected solely by an accidental spin rotation symmetry and fragile against spin-orbit coupling, while the arcs are protected by the first Chern number and one-dimensional winding number. Lastly, we discuss how topological quasiparticles can be captured from tunneling conductance spectra in U1-xThxBe13.
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