Nano-ploughed Josephson Junctions as on-chip Radiation Sources

TL;DR

This paper introduces a novel nano-etching technique to create highly transparent Josephson junctions integrated with mesoscopic devices, enabling on-chip millimeter wave radiation sources with potential applications in quantum electronics.

Contribution

It presents a new fabrication method using a modified AFM tip to produce weak links in superconductors, combining junctions with quantum dots for high-frequency radiation generation.

Findings

Junctions exhibit high transparency and stable characteristics.

Millimeter wave emission induces a bolometric effect in quantum point contacts.

The technique enables integration of Josephson junctions with mesoscopic devices.

Abstract

A new technique is presented which enables the fabrication of highly transparent Josephson junctions in combination with mesoscopic devices. We utilize a modified AFM tip to plough grooves into superconducting material, thus defining a weak link. This weak link is made within the superconducting split-gates, which are used to electrostatically form a conventional quantum dot and serves as a source of millimeter wave radiation around 100 GHz. We show the characteristics of typical junctions built and discuss their high-frequency properties. We find that the millimeter wave emission of the weak link leads to a bolometric effect in the case of quantum point contact spectroscopy.