Electron waiting times in hybrid junctions with topological superconductors

TL;DR

This paper studies electron waiting times in hybrid junctions with topological superconductors, revealing that waiting time distributions can serve as indicators of topological edge states and differ significantly from trivial superconductors.

Contribution

It introduces a scattering matrix approach to analyze waiting time distributions in topological superconducting junctions, highlighting their potential for detecting topological phases.

Findings

WTDs are sensitive to electron-hole reflection processes.

Topological superconductors show voltage-independent WTDs.

WTDs can distinguish trivial from topological superconductivity.

Abstract

We investigate the waiting time distributions (WTDs) of superconducting hybrid junctions, considering both conventional and topologically nontrivial superconductors hosting Majorana bound states at their edges. To this end, we employ a scattering matrix formalism that allows us to evaluate the waiting times between the transmissions and reflections of electrons or holes. Specifically, we analyze normal-metal-superconductor (NIS) junctions and NISIN junctions, where Cooper pairs are spatially split into different leads. The distribution of waiting times is sensitive to the simultaneous reflection of electrons and holes, which is enhanced by the zero-energy state in topological superconductors. For the NISIN junctions, the WTDs of trivial superconductors feature a sharp dependence on the applied voltage, while for topological ones they are mostly independent of it. This particular voltage dependence is again connected to the presence of topological edge states, showing that WTDs are a promising tool for identifying topological superconductivity.