Improving the Josephson energy in High-T$_c$ superconducting junctions for ultra-fast electronics

TL;DR

This paper demonstrates enhanced Josephson coupling in high-Tc superconducting junctions with ultrathin SrTiO3 barriers, promising for ultra-fast terahertz electronic devices.

Contribution

It reports the fabrication and characterization of vertical GdBa2Cu3O7−δ/SrTiO3 Josephson junctions with improved Josephson energy compared to planar arrays.

Findings

Josephson coupling observed for 1 nm and 2 nm barriers.

Maximum Josephson voltage of 8.9 mV at 12 K.

Potential for terahertz superconducting electronics.

Abstract

We report the electrical transport in vertical Josephson tunnel junctions (area 400 $\mu m$$^2$) using GdBa$_2$Cu$_3$O$_7$$_{-\delta}$ electrodes and SrTiO$_3$ as an insulating barrier (with thicknesses between 1 nm and 4 nm). The results show Josephson coupling for junctions with SrTiO$_3$ barriers of 1 nm and 2 nm. The latter displays a Josephson of 8.9 mV at 12 K. This value is larger than the usually observed in planar arrays of junctions. Our results are promising for the development of superconducting electronic devices in the terahertz regime.