Dynamic properties of high-Tc superconducting nano-junctions made with a focused helium ion beam

Abstract

The Josephson junction (JJ) is the corner stone of superconducting electronics and quantum information processing. While the technology for fabricating low $T_c$ JJ is mature and delivers quantum circuits able to reach the "quantum supremacy", the fabrication of reproducible and low-noise high-$T_c$ JJ is still a challenge to be taken up. Here we report on noise properties at RF frequencies of recently introduced high-$T_c$ Josephson nano-junctions fabricated by mean of a Helium ion beam focused at sub-nanometer scale on a ${\mathrm{YBa}}_2{\mathrm{Cu}}_3{\mathrm{O}}_7$ thin film. We show that their current-voltage characteristics follow the standard Resistively-Shunted-Junction (RSJ) circuit model, and that their characteristic frequency $f_c=(2e/h)I_c{R}_n$ reaches $\sim 300$ GHz at low temperature. Using the "detector response" method, we evidence that the Josephson oscillation linewidth is only limited by the thermal noise in the RSJ model for temperature ranging from $T\sim 20$ K to $75$ K. At lower temperature and for the highest He irradiation dose, the shot noise contribution must also be taken into account when approaching the tunneling regime. We conclude that these Josephson nano-junctions present the lowest noise level possible, which makes them very promising for future applications in the microwave and terahertz regimes.

References in corpus (13)

• Quantum information processing with superconducting circuits: a review
• Fractional ac Josephson effect in p- and d-wave superconductors
• Superconductor Digital Electronics: Scalability and Energy Efficiency Issues
• Superconducting nanowire for single-photon detection: progress, challenges and opportunities
• High-Quality Planar high-Tc Josephson Junctions
• Josephson junctions and SQUIDs created by focused helium ion beam irradiation of YBa${}_2$Cu${}_3$O${}_7$
• Quantum interference in an interfacial superconductor
• High-Tc Superconducting Quantum Interference Filters (SQIFs) made by ion irradiation
• High-Tc superconducting detector for highly-sensitive microwave magnetometry
• Static and Radio-frequency magnetic response of high Tc Superconducting Quantum Interference Filters made by ion irradiation
• Optical Nanoscopy of High-Tc Cuprate Nano-Constriction Devices Patterned by Helium Ion Beams
• Noise properties of nanoscale YBCO Josephson junctions
• Josephson oscillation linewidth of ion-irradiated YBa${}_2$Cu${}_3$O${}_7$ junctions

Cited by in corpus (2)

• Single-photon detection using high-temperature superconductors
• Temporal evolution of electric transport properties of YBCO Josephson junctions produced by focused Helium ion beam irradiation