Phase-locked magnetoconductance oscillations as a probe of Majorana edge states

TL;DR

This paper investigates how magnetoconductance oscillations in a superconducting ring can reveal the presence of Majorana edge states, distinguishing them from Dirac modes through phase locking behavior.

Contribution

It introduces a method to detect Majorana edge states via phase-locked magnetoconductance oscillations in a flux-biased superconducting ring.

Findings

Magnetoconductance oscillations are h/e-periodic with amplitude ~(e^2/h)N^{-1/2}.

Dirac modes produce independent oscillations at different contacts.

Majorana modes cause phase-locked oscillations across contacts.

Abstract

We calculate the Andreev conductance of a superconducting ring interrupted by a flux-biased Josephson junction, searching for electrical signatures of circulating edge states. Two-dimensional pair potentials of spin-singlet d-wave and spin-triplet p-wave symmetry support, respectively, (chiral) Dirac modes and (chiral or helical) Majorana modes. These produce h/e-periodic magnetoconductance oscillations of amplitude \simeq (e^{2}/h)N^{-1/2}, measured via an N-mode point contact at the inner or outer perimeter of the grounded ring. For Dirac modes the oscillations in the two contacts are independent, while for an unpaired Majorana mode they are phase locked by a topological phase transition at the Josephson junction.