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Portrait of Martin Leijnse; Photo: Kennet Ruona

Martin Leijnse

Professor, Member of NanoLund Management Group

Portrait of Martin Leijnse; Photo: Kennet Ruona

Band structure and end states in InAs/GaSb core-shell-shell nanowires

Author

  • Florinda Viñas Boström
  • Athanasios Tsintzis
  • Michael Hell
  • Martin Leijnse

Summary, in English

Quantum wells in InAs/GaSb heterostructures can be tuned to a topological regime associated with the quantum spin Hall effect, which arises due to an inverted band gap and hybridized electron and hole states. Here, we investigate electron-hole hybridization and the fate of the quantum spin Hall effect in a quasi-one-dimensional geometry, realized in a core-shell-shell nanowire with an insulator core and InAs and GaSb shells. We calculate the band structure for an infinitely long nanowire using k·p theory within the Kane model and the envelope function approximation, then map the result onto a Bernevig-Hughes-Zhang model which is used to investigate finite-length wires. Clearly, quantum spin Hall edge states cannot appear in the core-shell-shell nanowires which lack one-dimensional edges, but in the inverted band gap regime we find that the finite-length wires instead host localized states at the wire ends. These end states are not topologically protected; they are fourfold degenerate and split into two Kramers pairs in the presence of potential disorder along the axial direction. However, there is some remnant of the topological protection of the quantum spin Hall edge states in the sense that the end states are fully robust to (time-reversal preserving) angular disorder, as long as the bulk band gap is not closed.

Department/s

  • Solid State Physics
  • NanoLund: Center for Nanoscience

Publishing year

2020

Language

English

Publication/Series

Physical Review B

Volume

102

Issue

19

Document type

Journal article

Publisher

American Physical Society

Topic

  • Condensed Matter Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 2469-9950