Role of Topology and Symmetry for the Edge Currents of a 2D Superconductor

Fuente: arXiv
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Hauptverfasser: Holst, Maximilian F., Sigrist, Manfred, Fischer, Mark H.
Format: Preprint
Veröffentlicht: 2021
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author Holst, Maximilian F.
Sigrist, Manfred
Fischer, Mark H.
author_facet Holst, Maximilian F.
Sigrist, Manfred
Fischer, Mark H.
contents The bulk-boundary correspondence guarantees topologically protected edge states in a two-dimensional topological superconductor. Unlike in topological insulators, these edge states are, however, not connected to a quantized (spin) current as the electron number is not conserved in a Bogolyubov-de Gennes Hamiltonian. Still, edge currents are in general present. Here, we use the two-dimensional Rashba system as an example to systematically analyze the effect symmetry reductions have on the order-parameter mixing and the edge properties in a superconductor of Altland-Zirnbauer class DIII (time-reversal-symmetry preserving) and D (time-reversal-symmetry breaking). In particular, we employ both Ginzburg-Landau and microscopic modeling to analyze the bulk superconducting properties and edge currents appearing in a strip geometry. We find edge (spin) currents independent of bulk topology and associated topological edge states which evolve continuously even when going through a phase transition into a topological state. Our findings emphasize the importance of symmetry over topology for the understanding of the non-quantized edge currents.
format Preprint
id arxiv_https___arxiv_org_abs_2108_12337
institution arXiv
publishDate 2021
record_format arxiv
spellingShingle Role of Topology and Symmetry for the Edge Currents of a 2D Superconductor
Holst, Maximilian F.
Sigrist, Manfred
Fischer, Mark H.
Superconductivity
The bulk-boundary correspondence guarantees topologically protected edge states in a two-dimensional topological superconductor. Unlike in topological insulators, these edge states are, however, not connected to a quantized (spin) current as the electron number is not conserved in a Bogolyubov-de Gennes Hamiltonian. Still, edge currents are in general present. Here, we use the two-dimensional Rashba system as an example to systematically analyze the effect symmetry reductions have on the order-parameter mixing and the edge properties in a superconductor of Altland-Zirnbauer class DIII (time-reversal-symmetry preserving) and D (time-reversal-symmetry breaking). In particular, we employ both Ginzburg-Landau and microscopic modeling to analyze the bulk superconducting properties and edge currents appearing in a strip geometry. We find edge (spin) currents independent of bulk topology and associated topological edge states which evolve continuously even when going through a phase transition into a topological state. Our findings emphasize the importance of symmetry over topology for the understanding of the non-quantized edge currents.
title Role of Topology and Symmetry for the Edge Currents of a 2D Superconductor
topic Superconductivity
url https://arxiv.org/abs/2108.12337