Josephson effect in multiterminal topological junctions

A. Zazunov, R. Egger, M. Alvarado, and A. Levy Yeyati
Phys. Rev. B 96, 024516 – Published 26 July 2017

Abstract

We study the Josephson effect in a trijunction formed by two topological superconductor (TS) wires and a conventional s-wave superconductor. Using a boundary Green's function formalism, analytical results for the current-phase relation are obtained in various limiting cases by modeling the TS wires via the low-energy limit of a Kitaev chain. We show that Josephson transport critically depends on the spin canting angle θ between the boundary spin polarizations of the TS wires, which in turn suggests that the spin structure of Majorana states can be accessed through supercurrent measurements. We also extend the boundary Green's function approach to a more microscopic spinful wire model and thereby compute the dependence of θ on experimentally accessible parameters such as the Zeeman field and/or the chemical potential. Furthermore, we show that the equilibrium current-phase relation between both TS wires exhibits a robust 4π periodicity since the conventional superconducting lead effectively locks the fermion parity of the trijunction.

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  • Received 16 June 2017

DOI:https://doi.org/10.1103/PhysRevB.96.024516

©2017 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

A. Zazunov1, R. Egger1, M. Alvarado2, and A. Levy Yeyati2

  • 1Institut für Theoretische Physik, Heinrich-Heine-Universität, D-40225 Düsseldorf, Germany
  • 2Departamento de Física Teórica de la Materia Condensada C-V, Condensed Matter Physics Center (IFIMAC) and Instituto Nicolás Cabrera, Universidad Autónoma de Madrid, E-28049 Madrid, Spain

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Issue

Vol. 96, Iss. 2 — 1 July 2017

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