Topology protection-unprotection transition: an example from multi-terminal superconducting nanostructures

Abstract

We show theoretically that in the superconducting nanostructures the gapped states of different topology are not always protected by separating gapped states. Depending on the structure design parameters, they can be either protected or not, with a protection-unprotection transition separating these two distinct situations. We build up a general theoretical description of the transition vicinity in the spirit of Landau theory. We speculate that similar protection-unprotection transitions may also occur for other realizations of topological protection in condensed matter systems.

References in corpus (9)

• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Signatures of Majorana fermions in hybrid superconductor-semiconductor nanowire devices
• Observation of Majorana Fermions in Ferromagnetic Atomic Chains on a Superconductor
• Observation of topological surface state quantum Hall effect in an intrinsic three-dimensional topological insulator
• The $\omega$-SQUIPT: phase-engineering of Josephson topological materials
• Topological transconductance quantization in a four-terminal Josephson junction
• Singularities of Andreev spectrum in multi-terminal Josephson junction
• Closing the proximity gap in a metallic Josephson junction between three superconductors
• Order, disorder and tunable gaps in the spectrum of Andreev bound states in a multi-terminal superconducting device

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• Full tomography of topological Andreev bands in graphene Josephson junctions
• Drastic effect of weak interaction near special points in semiclassical multiterminal superconducting nanostructures