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Magnetic-Field-Independent Subgap States in Hybrid Rashba Nanowires

Jünger, Christian ; Delagrange, Raphaëlle ; Chevallier, Denis ; Lehmann, Sebastian LU ; Dick, Kimberly A. LU ; Thelander, Claes LU ; Klinovaja, Jelena ; Loss, Daniel ; Baumgartner, Andreas and Schönenberger, Christian (2020) In Physical Review Letters 125(1).
Abstract

Subgap states in semiconducting-superconducting nanowire hybrid devices are controversially discussed as potential topologically nontrivial quantum states. One source of ambiguity is the lack of an energetically and spatially well defined tunnel spectrometer. Here, we use quantum dots directly integrated into the nanowire during the growth process to perform tunnel spectroscopy of discrete subgap states in a long nanowire segment. In addition to subgap states with a standard magnetic field dependence, we find topologically trivial subgap states that are independent of the external magnetic field, i.e., that are pinned to a constant energy as a function of field. We explain this effect qualitatively and quantitatively by taking into... (More)

Subgap states in semiconducting-superconducting nanowire hybrid devices are controversially discussed as potential topologically nontrivial quantum states. One source of ambiguity is the lack of an energetically and spatially well defined tunnel spectrometer. Here, we use quantum dots directly integrated into the nanowire during the growth process to perform tunnel spectroscopy of discrete subgap states in a long nanowire segment. In addition to subgap states with a standard magnetic field dependence, we find topologically trivial subgap states that are independent of the external magnetic field, i.e., that are pinned to a constant energy as a function of field. We explain this effect qualitatively and quantitatively by taking into account the strong spin-orbit interaction in the nanowire, which can lead to a decoupling of Andreev bound states from the field due to a spatial spin texture of the confined eigenstates. This result constitutes an important step forward in the research on superconducting subgap states in nanowires, such as Majorana bound states.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review Letters
volume
125
issue
1
article number
017701
publisher
American Physical Society
external identifiers
  • scopus:85087890265
  • pmid:32678659
ISSN
0031-9007
DOI
10.1103/PhysRevLett.125.017701
language
English
LU publication?
yes
id
c1372a88-6c7e-4573-a593-28a49bd30146
date added to LUP
2020-07-29 11:19:13
date last changed
2024-05-01 14:05:57
@article{c1372a88-6c7e-4573-a593-28a49bd30146,
  abstract     = {{<p>Subgap states in semiconducting-superconducting nanowire hybrid devices are controversially discussed as potential topologically nontrivial quantum states. One source of ambiguity is the lack of an energetically and spatially well defined tunnel spectrometer. Here, we use quantum dots directly integrated into the nanowire during the growth process to perform tunnel spectroscopy of discrete subgap states in a long nanowire segment. In addition to subgap states with a standard magnetic field dependence, we find topologically trivial subgap states that are independent of the external magnetic field, i.e., that are pinned to a constant energy as a function of field. We explain this effect qualitatively and quantitatively by taking into account the strong spin-orbit interaction in the nanowire, which can lead to a decoupling of Andreev bound states from the field due to a spatial spin texture of the confined eigenstates. This result constitutes an important step forward in the research on superconducting subgap states in nanowires, such as Majorana bound states. </p>}},
  author       = {{Jünger, Christian and Delagrange, Raphaëlle and Chevallier, Denis and Lehmann, Sebastian and Dick, Kimberly A. and Thelander, Claes and Klinovaja, Jelena and Loss, Daniel and Baumgartner, Andreas and Schönenberger, Christian}},
  issn         = {{0031-9007}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{American Physical Society}},
  series       = {{Physical Review Letters}},
  title        = {{Magnetic-Field-Independent Subgap States in Hybrid Rashba Nanowires}},
  url          = {{http://dx.doi.org/10.1103/PhysRevLett.125.017701}},
  doi          = {{10.1103/PhysRevLett.125.017701}},
  volume       = {{125}},
  year         = {{2020}},
}