Nonlocal conductance reveals helical superconductors

TL;DR

This paper proposes that measuring nonlocal charge conductance in a superconducting ring can definitively identify helical superconductors, which host time-reversal invariant topological Majorana modes, offering a more robust detection method.

Contribution

It introduces a novel detection scheme based on nonlocal conductance measurements to identify helical superconductors, overcoming limitations of previous methods.

Findings

Nonlocal conductance reveals helical Majorana modes

Proposed experiments provide robust signatures of helical superconductivity

Detection scheme is more definitive than spin or local charge transport

Abstract

Helical superconductors form a two dimensional, time-reversal invariant topological phase characterized by a Kramers pair of Majorana edge modes (helical Majorana modes). Existing detection schemes to identify this phase rely either on spin transport properties, which are quite difficult to measure, or on local charge transport, which allows only a partial identification. Here we show that the presence of helical Majorana modes can be unambiguously revealed by measuring the nonlocal charge conductance. Focusing on a superconducting ring, we suggest two experiments that provide unique and robust signatures to detect the helical superconductor phase.