Superconducting insulators and localization of Cooper pairs

Communications Physics. 2021. Vol. 4. Article 146.

Arutyunov K., Lehtinen J. S., Radkevich A. A., Semenov A. G., Zaikin A. D.

Rapid miniaturization of electronic devices and circuits demands profound understanding of
fluctuation phenomena at the nanoscale. Superconducting nanowires – serving as important
building blocks for such devices – may seriously suffer from fluctuations which tend to
destroy long-range order and suppress superconductivity. In particular, quantum phase slips
(QPS) proliferating at low temperatures may turn a quasi-one-dimensional superconductor
into a resistor or an insulator. Here, we introduce a physical concept of QPS-controlled
localization of Cooper pairs that may occur even in uniform nanowires without any dielectric
barriers being a fundamental manifestation of the flux-charge duality in superconductors. We
demonstrate – both experimentally and theoretically – that deep in the “insulating” state such
nanowires actually exhibit non-trivial superposition of superconductivity and weak Coulomb
blockade of Cooper pairs generated by quantum tunneling of magnetic fluxons across
the wire.

Keywords: nanotechnology, нанотехнологии, quantum fluctuations, quantum nanoelectronics, Квантовые флуктуации, квантовая наноэлектроника, сверхпроводимость в наноразмерных системах, nanoscale superconductivity

Publication based on the results of: Квантовые эффекты в низкоразмерных гибридных наноструктурах (2022)