Dresden 2017 – scientific programme

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MA: Fachverband Magnetismus

MA 59: Topological Insulators II (jointly with DS, HL, O, TT)

MA 59.7: Talk

Friday, March 24, 2017, 11:00–11:15, HSZ 04

Is SmB₆ a failed superconductor — •Onur Erten — Max Planck Institute for the Physics of Complex Systems, Dresden

The classic theory of superfluids and superconductors is founded on London’s idea of “wavefunction rigidity", in which gradients of the phase of the ground-state condensate carry the superflow. However, the study of neutral superfluids teaches that a stable superflow also requires the topological quantization of circulation: when this is absent, as in the case of He-3A, the superflow is unstable. Here, we generalize this idea to charged superfluids, introducing the concept of a failed superconductor in which a higher order parameter manifold topologically destablizes vortices, causing a rapid decay of supercurrents, giving rise to a novel diamagnetic insulator. We apply this idea to the case of SmB₆, arguing that the observation of a gapless diamagnetic Fermi surface within an insulating bulk can be understood as a failed odd-frequency superconductor. Our results enable us to understand the linear specific heat of SmB₆ in terms of a neutral Majorana Fermi surface and lead us to predict that in low fields, SmB₆ will develop a Meissner effect.