Transport signatures of a junction between a quantum spin Hall system and a chiral topological superconductor

We investigate transport through a normal-superconductor (NS) junction made from a quantum spin Hall (QSH) system with helical edge states and a two-dimensional (2D) chiral topological superconductor (TSC) having a chiral Majorana edge mode. We employ a two-dimensional extended four-band model for H...

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Bibliographic Details
Published in:Physical review. B 2020-06, Vol.101 (23), p.1, Article 235308
Main Authors: Novik, E. G., Trauzettel, B., Recher, P.
Format: Article
Language:English
Subjects:
Quantum wells
Resistance
Signatures
Superconductivity
Topological superconductors
Two dimensional models
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Summary:We investigate transport through a normal-superconductor (NS) junction made from a quantum spin Hall (QSH) system with helical edge states and a two-dimensional (2D) chiral topological superconductor (TSC) having a chiral Majorana edge mode. We employ a two-dimensional extended four-band model for HgTe-based quantum wells in a magnetic (Zeeman) field and subject to s-wave superconductivity. We show using the Bogoliubov-de Gennes scattering formalism that this structure provides a striking transport signal of a 2D TSC. As a function of the sample width (or Fermi energy) the conductance resonances go through a sequence of 2e2/h (nontrivial phase) and 4e2/h plateaux (trivial phase) which fall within the region of a nonzero Chern number (2D limit) as the sample width becomes large. These signatures are a manifestation of the topological nature of the QSH effect and the TSC.
ISSN:2469-9950
2469-9969
DOI:10.1103/PhysRevB.101.235308