Fate of the superconducting state in floating islands of hybrid nanowire devices

TL;DR

This study explores how different device configurations affect the suppression of superconductivity in hybrid nanowire islands under transport current, revealing distinct mechanisms and relaxation regimes that influence superconducting stability.

Contribution

It identifies three fundamentally different suppression mechanisms of superconductivity in hybrid nanowire islands depending on device layout and reservoir type.

Findings

Superconductivity is suppressed by critical current, voltage, or Joule power depending on device configuration.

The collapse mechanism depends on the ratio of dwell time to electron-phonon relaxation time.

Different relaxation regimes are realized based on the coupling to reservoirs.

Abstract

We investigate the impact of transport current on the superconducting order parameter in superconducting islands in full-shell epitaxial Al-InAs nanowires. Depending on a device layout, the suppression of superconductivity occurs in three fundamentally different ways -- by a critical current in the case of superconducting reservoirs and by a critical voltage or by a critical Joule power in the case of normal reservoirs. In the latter case, the collapse of the superconducting state depends on the ratio of the dwell time and the electron-phonon relaxation time of quasiparticles in the island. For low resistive and high resistive coupling to the reservoirs, respectively, the relaxation-free regime and the strong electron-phonon relaxation regime are realized. Our results shed light on potential shortcomings of finite-bias transport spectroscopy in floating islands.