Direct writing of high temperature superconducting Josephson junctions using a thermal scanning probe

TL;DR

This paper introduces a novel thermal scanning probe technique to directly inscribe superconducting Josephson junctions into YBCO microstrips, enabling scalable quantum circuit fabrication at liquid nitrogen temperatures.

Contribution

It presents the first method to create Josephson-like nanojunctions using a thermal probe, allowing in-situ property modification and scalable quantum device fabrication.

Findings

Successfully inscribed Josephson nanojunctions with clear Josephson effects

Reduced critical current by over an order of magnitude

Demonstrated potential for scalable quantum circuit integration

Abstract

In this letter, we demonstrate for the first time the creation of Josephson-like superconducting nanojunctions using a thermal scanning probe to directly inscribe weak links into microstrips of YBa2Cu3O7-x (YBCO). Our method effectively reduces the critical current (Ic) over an order of magnitude. The resulting nanobridges exhibit clear evidence of Josephson effects, of SNS-type junctions, as shown by both the DC and AC Josephson effects. This approach provides a novel and flexible method for scaling up quantum mechanical circuits that operate at liquid nitrogen temperatures. Additionally, it offers a promising pathway for modifying properties of the junctions in-situ and post fabrication.