Selective Area Grown Semiconductor-Superconductor Hybrids: A Basis for Topological Networks

TL;DR

This paper presents a novel method for growing semiconductor-superconductor hybrid nanowires with complex network geometries, demonstrating their potential for scalable topological quantum devices.

Contribution

It introduces a selective area growth technique for InAs/Al nanowires enabling arbitrary network structures with demonstrated topological properties.

Findings

Hard induced gap observed in transport measurements

Temperature-dependent Coulomb blockade features match theory

Strong spin-orbit coupling with micron-scale coherence length

Abstract

We introduce selective area grown hybrid InAs/Al nanowires based on molecular beam epitaxy, allowing arbitrary semiconductor-superconductor networks containing loops and branches. Transport reveals a hard induced gap and unpoisoned 2e-periodic Coulomb blockade, with temperature dependent 1e features in agreement with theory. Coulomb peak spacing in parallel magnetic field displays overshoot, indicating an oscillating discrete near-zero subgap state consistent with device length. Finally, we investigate a loop network, finding strong spin-orbit coupling and a coherence length of several microns. These results demonstrate the potential of this platform for scalable topological networks among other applications.