Speaker
Jonathan Baugh
(University of Waterloo)
Description
The Josephson effect in a nanowire-based superconductor-normal-superconductor (SNS) junction is studied theoretically and experimentally, focusing on the effects of nanoscale confinement on the current-phase relationship of the junction. We identify a new type of Josephson interference based on the coupling of an applied axial magnetic flux to N-section Andreev quasiparticles (bound and continuum states) occupying electronic subtends of non-zero orbital angular momentum. The Bogoliubov-de Gennes equations are solved while considering the transverse subbands in the N-section, yielding energy-versus-phase curves that are shifted in phase in the presence of the flux. A similar phase shift is observed in the continuum current of the junction. Experimental observations of similar oscillations of critical current in a Nb-InAs nanowire-Nb junction are described, and analyzed in the context of our theoretical model. Since this type of semiconductor-superconductor junction can, in theory, support Majorana fermions, this orbital interference effect must be taken into account when looking for topological signatures in the critical current versus field and temperature.
Primary author
Jonathan Baugh
(University of Waterloo)
Co-authors
Mr
Greg Holloway
(University of Waterloo)
Mr
Kaveh Gharavi
(University of Waterloo)
