Intrinsically shunted Josephson junctions for electronics applications

Belogolovskii, Mikhail; Zhitlukhina, Elena; Lacquaniti, V.; Leo, Natascia De; Fretto, Matteo; Sosso, A.

doi:10.1063/1.4995622

Cited by 27 publications

(10 citation statements)

References 72 publications

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“…To conclude, we note that there are other types of junctions which exhibit self-shunting, have sufficiently high Jc, and rela-tively high IcRN values, e.g., SINIS [47], SNIS [48], [49], etc., see a recent review [50]. However, discussion of their pros and cons goes beyond the scope of this manuscript because we are not considering them for the use in our fabrication processes.…”

Section: B Nb/si:nb/nb Josephson Junctionsmentioning

confidence: 99%

Superconductor Electronics Fabrication Process with MoNx Kinetic Inductors and Self-Shunted Josephson Junctions

Tolpygo

Bolkhovsky

Oates

et al. 2018

IEEE Trans. Appl. Supercond.

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Recent progress in superconductor electronics fabrication has enabled single-flux-quantum (SFQ) digital circuits with close to one million Josephson junctions (JJs) on 1-cm 2 chips. Increasing the integration scale further is challenging because of the large area of SFQ logic cells, mainly determined by the area of resistively shunted Nb/AlOx-Al/Nb JJs and geometrical inductors utilizing multiple layers of Nb. To overcome these challenges, we are developing a fabrication process with self-shunted high-Jc JJs and compact thin-film MoNx kinetic inductors instead of geometrical inductors. We present fabrication details and properties of MoNx films with a wide range of Tc, including residual stress, electrical resistivity, critical current, and magnetic field penetration depth λ0. As kinetic inductors, we implemented Mo2N films with Tc about 8 K, λ0 about 0.51 μm, and inductance adjustable in the range from 2 to 8 pH/sq. We also present data on fabrication and electrical characterization of Nb-based self-shunted JJs with AlOx tunnel barriers and Jc = 0.6 mA/μm 2 , and with 10-nm thick Si1-xNbx barriers, with x from 0.03 to 0.15, fabricated on 200-mm wafers by cosputtering. We demonstrate that the electron transport mechanism in Si1-xNbx barriers at x < 0.08 is inelastic resonant tunneling via chains of multiple localized states. At larger x, their Josephson characteristics are strongly dependent on x and residual stress in Nb electrodes, and in general are inferior to AlOx tunnel barriers.

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Section: B Nb/si:nb/nb Josephson Junctionsmentioning

confidence: 99%

Superconductor Electronics Fabrication Process with MoNx Kinetic Inductors and Self-Shunted Josephson Junctions

Tolpygo

Bolkhovsky

Oates

et al. 2018

IEEE Trans. Appl. Supercond.

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“…As can be seen in Figure (c), the differential resistance around I sd = 0 is not strictly zero but R 0 ≈ 200 Ω. This is due to the effect of thermal fluctuations in the junction and can be understood in the framework of the theory by Ambegaokar and Halperin. , In fact, the McCumber parameter β c of the junction is β c = ω J τ RC , with ω J = 2 eV c / ℏ the characteristic Josephson frequency ( ℏ is the reduced Planck constant, V c = I c R N , with I c the critical current) and τ RC = R N C the decay time within the RCSJ model. − Approximating the junction capacitance C with a parallel plate capacitor model, we obtain β c = 1.2 × 10 –5 ≪ 1 (for details, see the Supporting Information). Thus, the junction is in the overdamped regime, and the nonvanishing junction voltage even in the limit I sd → 0 can be attributed to a phase-slip resistance contribution.…”

Section: Resultsmentioning

confidence: 95%

Evidence of Josephson Coupling in a Few-Layer Black Phosphorus Planar Josephson Junction

et al. 2022

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Setting up strong Josephson coupling in van der Waals materials in close proximity to superconductors offers several opportunities both to inspect fundamental physics and to develop cryogenic quantum technologies. Here we show evidence of Josephson coupling in a planar few-layer black phosphorus junction. The planar geometry allows us to probe the junction behavior by means of external gates, at different carrier concentrations. Clear signatures of Josephson coupling are demonstrated by measuring supercurrent flow through the junction at milli-Kelvin temperatures. Manifestation of a Fraunhofer pattern with a transverse magnetic field is also reported, confirming the Josephson coupling. These findings represent evidence of proximity Josephson coupling in a planar junction based on a van der Waals material beyond graphene and will expedite further studies, exploiting the peculiar properties of exfoliated black phosphorus thin flakes.

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“…Форма вольт-амперних характеристик та присутність вище згаданих ознак свідчить про одержання цим способом Джозефсонових переходів SNIS-типу. Розроблені технології можуть бути використані для масового виготовлення Джозефсонових SISпереходів з метою їхніх застосувань в сучасній мікроелектроніці [17,18]. Автори вдячні В. І. Шниркову, В. М. Краснову та Т. Голоду за участь в обговоренні результатів.…”

Section: методика вимірюваньunclassified

Characteristics of Josephson Nb/Al/AlO$_{x}$/Nb Contacts Formed by Simplified Method

Kalenyuk¹,

Shapovalov²

2022

Metallofiz. Noveishie Tekhnol.

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Intrinsically shunted Josephson junctions for electronics applications

Cited by 27 publications

References 72 publications

Superconductor Electronics Fabrication Process with MoNx Kinetic Inductors and Self-Shunted Josephson Junctions

Superconductor Electronics Fabrication Process with MoNx Kinetic Inductors and Self-Shunted Josephson Junctions

Evidence of Josephson Coupling in a Few-Layer Black Phosphorus Planar Josephson Junction

Characteristics of Josephson Nb/Al/AlO$_{x}$/Nb Contacts Formed by Simplified Method

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