Tunable effective length of fractional Josephson junctions

verfasst von
Daniel Frombach, Patrik Recher
Abstract

Topological Josephson junctions (TJJs) have been a subject of widespread interest due to their hosting of Majorana zero modes. In long junctions, i.e. junctions where the junction length exceeds the superconducting coherence length, TJJs manifest themselves in specific features of the critical current (Beenakker 2013 Phys. Rev. Lett. 110 017003). Here we propose to couple the helical edge states mediating the TJJ to additional channels or quantum dots, by which the effective junction length can be increased by tunable parameters associated with these couplings, so that such measurements become possible even in short junctions. Besides effective low-energy models that we treat analytically, we investigate realizations by a Kane-Mele model with edge passivation and treat them numerically via tight binding models. In each case, we explicitly calculate the critical current using the Andreev bound state spectrum and show that it differs in effectively long junctions in the cases of strong and weak parity changing perturbations (quasiparticle poisoning).

Externe Organisation(en)
Technische Universität Braunschweig
Laboratory for Emerging Nanometrology Braunschweig (LENA)
Typ
Artikel
Journal
Journal of Physics Condensed Matter
Band
34
ISSN
0953-8984
Publikationsdatum
23.02.2022
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Werkstoffwissenschaften (insg.), Physik der kondensierten Materie
Elektronische Version(en)
https://doi.org/10.1088/1361-648X/ac4dbc (Zugang: Offen)