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Coupling and braiding Majorana bound states in networks defined in proximate two-dimensional electron gases

Hell, Michael LU ; Flensberg, Karsten and Leijnse, Martin LU (2017) In Physical Review B 96(3).
Abstract

Two-dimensional electron gases with strong spin-orbit coupling covered by a superconducting layer offer a flexible and potentially scalable platform for Majorana networks. We predict Majorana bound states (MBSs) to appear for experimentally achievable parameters and realistic gate potentials in two designs: either underneath a narrow stripe of a superconducting layer (S stripes) or where a narrow stripe has been removed from a uniform layer (N stripes). The coupling of the MBSs can be tuned for both types in a wide range (<1neV to >10μeV) using gates placed adjacent to the stripes. For both types, we numerically compute the local density of states for two parallel Majorana-stripe ends as well as Majorana trijunctions formed in a... (More)

Two-dimensional electron gases with strong spin-orbit coupling covered by a superconducting layer offer a flexible and potentially scalable platform for Majorana networks. We predict Majorana bound states (MBSs) to appear for experimentally achievable parameters and realistic gate potentials in two designs: either underneath a narrow stripe of a superconducting layer (S stripes) or where a narrow stripe has been removed from a uniform layer (N stripes). The coupling of the MBSs can be tuned for both types in a wide range (<1neV to >10μeV) using gates placed adjacent to the stripes. For both types, we numerically compute the local density of states for two parallel Majorana-stripe ends as well as Majorana trijunctions formed in a tuning-fork geometry. The MBS coupling between parallel Majorana stripes can be suppressed below 1 neV for potential barriers in the meV range for separations of about 200 nm. We further show that the MBS couplings in a trijunction can be gate controlled in a range similar to the intrastripe coupling while maintaining a sizable gap to the excited states (tens of μeV). Altogether, this suggests that braiding can carried out on a time scale of 10-100 ns.

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Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Review B
volume
96
issue
3
publisher
American Physical Society
external identifiers
  • scopus:85027276647
  • wos:000406631500007
ISSN
2469-9950
DOI
10.1103/PhysRevB.96.035444
language
English
LU publication?
yes
id
f7bdfe52-f6cc-47a0-82b8-c483ba6b77c3
date added to LUP
2017-08-31 11:08:23
date last changed
2017-09-18 11:43:36
@article{f7bdfe52-f6cc-47a0-82b8-c483ba6b77c3,
  abstract     = {<p>Two-dimensional electron gases with strong spin-orbit coupling covered by a superconducting layer offer a flexible and potentially scalable platform for Majorana networks. We predict Majorana bound states (MBSs) to appear for experimentally achievable parameters and realistic gate potentials in two designs: either underneath a narrow stripe of a superconducting layer (S stripes) or where a narrow stripe has been removed from a uniform layer (N stripes). The coupling of the MBSs can be tuned for both types in a wide range (&lt;1neV to &gt;10μeV) using gates placed adjacent to the stripes. For both types, we numerically compute the local density of states for two parallel Majorana-stripe ends as well as Majorana trijunctions formed in a tuning-fork geometry. The MBS coupling between parallel Majorana stripes can be suppressed below 1 neV for potential barriers in the meV range for separations of about 200 nm. We further show that the MBS couplings in a trijunction can be gate controlled in a range similar to the intrastripe coupling while maintaining a sizable gap to the excited states (tens of μeV). Altogether, this suggests that braiding can carried out on a time scale of 10-100 ns.</p>},
  articleno    = {035444},
  author       = {Hell, Michael and Flensberg, Karsten and Leijnse, Martin},
  issn         = {2469-9950},
  language     = {eng},
  month        = {07},
  number       = {3},
  publisher    = {American Physical Society},
  series       = {Physical Review B},
  title        = {Coupling and braiding Majorana bound states in networks defined in proximate two-dimensional electron gases},
  url          = {http://dx.doi.org/10.1103/PhysRevB.96.035444},
  volume       = {96},
  year         = {2017},
}