Intrinsically shunted Josephson junctions for electronics applications
M. Belogolovskii1,2, E. Zhitlukhina2,3, V. Lacquaniti4, N. De Leo4, M. Fretto4, and A. Sosso4
1Institute for Metal Physics, Kyiv 03142, Ukraine
2Donetsk National University, Vinnytsia 21021, Ukraine
3Donetsk Institute for Physics and Engineering, Kyiv 03028, Ukraine
4National Institute for Metrological Research, Torino 10135, Italy
Received February 14, 2017
Conventional Josephson metal-insulator-metal devices are inherently underdamped and exhibit hysteretic cur-rent-voltage response due to a very high subgap resistance compared to that in the normal state. At the same time, overdamped junctions with single-valued characteristics are needed for most superconducting digital applications. The usual way to overcome the hysteretic behavior is to place an external low-resistance normal-metal shunt in parallel with each junction. Unfortunately, such solution results in a considerable complication of the circuitry design and introduces parasitic inductance through the junction. This paper provides a concise overview of some generic approaches that have been proposed in order to realize internal shunting in Josephson heterostructures with a barrier that itself contains the desired resistive component. The main attention is paid to self-shunted devices with local weak-link transmission probabilities that are so strongly disordered in the inter-face plane that transmission probabilities are tiny for the main part of the transition region between two super-conducting electrodes, while a small part of the interface is well transparent. We discuss the possibility of realizing a universal bimodal distribution function and emphasize advantages of such junctions that can be considered as a new class of self-shunted Josephson devices promising for practical applications in superconducting electronics operating at 4.2 K.
PACS: 85.25.Cp Josephson devices;
Key words: Josephson junctions, charge transport, internal shunting, disordered interfaces, superconducting electronics.
Published online: May 25, 2017
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ISSN: 0132-6414 (Print) | ISSN: 1816-0328 (Online)