Andreev interference in the surface accumulation layer of half-shell InAsSb/Al hybrid nanowires

TL;DR

This study investigates the charge carrier distribution in InAsSb/Al nanowires using Andreev interference, revealing tunable surface accumulation layers crucial for hybrid quantum device design.

Contribution

It demonstrates gate-tunable surface accumulation layers in InAsSb/Al nanowires via Andreev interference, advancing understanding of their spatial charge distribution.

Findings

Periodic modulation of switching current observed

Flux quantum corresponds to nanowire diameter

Surface accumulation layer is gate-tunable

Abstract

Understanding the spatial distribution of charge carriers in III-V nanowires proximity coupled to superconductors is important for the design and interpretation of experiments based on hybrid quantum devices. In this letter, the gate-dependent surface accumulation layer of InAsSb/Al nanowires was studied by means of Andreev interference in a parallel magnetic field. Both uniform hybrid nanowires and devices featuring a short Josephson junction fabricated by shadow lithography, exhibited periodic modulation of the switching current. The period corresponds to a flux quantum through the nanowire diameter and is consistent with Andreev bound states occupying a cylindrical surface accumulation layer. The spatial distribution was tunable by a gate potential as expected from electrostatic models.