Hybrid semiconductor-superconductor nanowires have emerged as a promising platform for realizing topological superconductivity (TSC). Here, we present a route to TSC using magnetic flux applied to a full superconducting shell surrounding a semiconducting nanowire core. Tunneling into the core reveals a hard induced gap near zero applied flux, corresponding to zero phase winding, and a gapped region with a discrete zero-energy state around one applied flux quantum, corresponding to 2π phase winding. Theoretical analysis indicates that the winding of the superconducting phase can induce a transition to a topological phase supporting Majorana zero modes. Measured Coulomb blockade peak spacing around one flux quantum shows a length dependence that is consistent with the existence of Majorana modes at the ends of the nanowire.
Enhanced topological superconductivity in spatially modulated planar Josephson junctions
We propose a semiconductor-superconductor hybrid device for realizing topological superconductivity and
Majorana zero modes consisting of a planar Josephson junction structure with periodically modulated junction
width. By performing a numerical analysis of the effective model describing the low-energy physics of the hybrid
structure, we demonstrate that the modulation of the junction width results in a substantial enhancement of the
topological gap and, consequently, of the robustness of the topological superconducting phase and associated
Majorana zero modes. This enhancement is due to the formation of minibands with strongly renormalized
effective parameters, including stronger spin-orbit coupling, generated by the effective periodic potential induced
by the modulated structure. In addition to a larger topological gap, the proposed device supports a topological
superconducting phase that covers a significant fraction of the parameter space, including the low Zeeman field
regime, in the absence of a superconducting phase difference across the junction. Furthermore, the optimal
regime for operating the device can be conveniently accessed by tuning the potential in the junction region
using, for example, a top gate.
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- Award ID(s):
- 2014156
- PAR ID:
- 10476247
- Publisher / Repository:
- American Physical Society
- Date Published:
- Journal Name:
- Physical Review B
- Volume:
- 104
- Issue:
- 15
- ISSN:
- 2469-9950
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1103/PhysRevB.104.155428
