$4\pi$periodic supercurrent tuned by an axial magnetic flux in topological insulator nanowires
Abstract
Topological insulator (TI) nanowires in proximity with conventional superconductors have been proposed as a tunable platform to realize topological superconductivity and Majorana zero modes (MZM). The tuning is done using an axial magnetic flux $\Phi$ which allows transforming the system from trivial at $\Phi=0$ to topologically nontrivial when half a magnetic flux quantum $\Phi_0/2$ threads the wire's crosssection. Here we explore the expected topological transition in TIwirebased Josephson junctions as a function of magnetic flux by probing the $4\pi$periodic fraction of the supercurrent, which is considered as an indicator of topological superconductivity. Our data suggest that this $4\pi$periodic supercurrent is at lower magnetic field largely of trivial origin, but that at magnetic fields above $\sim\Phi_{0}/4$ topological $4\pi$periodic supercurrents take over.
 Publication:

arXiv eprints
 Pub Date:
 October 2021
 arXiv:
 arXiv:2110.05143
 Bibcode:
 2021arXiv211005143F
 Keywords:

 Condensed Matter  Mesoscale and Nanoscale Physics;
 Condensed Matter  Superconductivity