Tunable effective length of fractional Josephson junctions

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Autoren

  • Daniel Frombach
  • Patrik Recher

Externe Organisationen

  • Technische Universität Braunschweig
  • Laboratory for Emerging Nanometrology Braunschweig (LENA)
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Details

OriginalspracheEnglisch
Aufsatznummer164005
FachzeitschriftJournal of Physics Condensed Matter
Jahrgang34
Ausgabenummer16
PublikationsstatusVeröffentlicht - 23 Feb. 2022
Extern publiziertJa

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).

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Tunable effective length of fractional Josephson junctions. / Frombach, Daniel; Recher, Patrik.
in: Journal of Physics Condensed Matter, Jahrgang 34, Nr. 16, 164005, 23.02.2022.

Publikation: Beitrag in FachzeitschriftArtikelForschungPeer-Review

Frombach D, Recher P. Tunable effective length of fractional Josephson junctions. Journal of Physics Condensed Matter. 2022 Feb 23;34(16):164005. doi: 10.1088/1361-648X/ac4dbc
Frombach, Daniel ; Recher, Patrik. / Tunable effective length of fractional Josephson junctions. in: Journal of Physics Condensed Matter. 2022 ; Jahrgang 34, Nr. 16.
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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). ",
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N2 - 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).

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