Semiconductor–superconductor hybrid systems are promising
candidates for the realization of Majorana fermions and topological order, i.e.
topologically protected degeneracies, in solid state devices. We show that the
topological order is mirrored in the excitation spectra and can be observed
in nonlinear Coulomb blockade transport through a ring-shaped nanowire.
Especially, the excitation spectrum is almost independent of magnetic flux in
the topologically trivial phase but acquires a characteristic h/e magnetic flux
periodicity in the non-trivial phase. The transition between the trivial and nontrivial
phase is reflected in the closing and reopening of an excitation gap. We
show that the signatures of topological order are robust against details of the
geometry, electrostatic disorder and the existence of additional subbands and
only rely on the topology of the nanowire and the existence of a superconducting
gap. Finally, we show that the coherence length in the non-trivial phase is much
longer than in the trivial phase. This opens the possibility to coat the nanowire
with superconducting nanograins and thereby significantly reduce the current
due to cotunnelling of Cooper pairs and to enhance the Coulomb charging energy
without destroying the superconducting gap.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:91237 |
| Date | 03 May 2024 |
| Creators | Zocher, Björn, Horsdal, Mats, Rosenow, Bernd |
| Publisher | IOP Publishing |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:article, info:eu-repo/semantics/article, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 085003 |
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