Long-lived Andreev states as evidence for protected hinge modes in a bismuth nanoring Josephson junction

Abstract

Second-order topological insulators are characterized by helical, non-spin-degenerate, one-dimensional states running along opposite crystal hinges, with no backscattering. Injecting superconducting pairs therefore entails splitting Cooper pairs into two families of helical Andreev states of opposite helicity, one at each hinge. Here we provide evidence for such separation via the measurement and analysis of switching supercurrent statistics of a crystalline nanoring of bismuth. Using a phenomenological model of two helical Andreev hinge modes, we find that pairs relax at a rate comparable to individual quasiparticles, in contrast with the much faster pair relaxation of non-topological systems. This constitutes a unique tell-tale sign of the spatial separation of topological helical hinges.

10 pages, 5 figures

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Cited by in corpus (8)

• Current-phase relation of a WTe2 Josephson junction
• Direct measurement of a $\sin (2\phi )$ current phase relation in a graphene superconducting quantum interference device
• Anomalous $h/2e$ periodicity and Majorana zero modes in chiral Josephson junctions
• STM observation of the hinge-states of bismuth nanocrystals
• Unveiling Topological Hinge States in the Higher-Order Topological Insulator WTe${}_2$ Based on the Fractional Josephson Effect
• Andreev qubit readout from dynamic interference supercurrent
• Majorana vortex phases in time-reversal invariant higher-order topological insulators and topologically trivial insulators
• Probing the topological protection of edge states in multilayer tungsten ditelluride with the superconducting proximity effect