Tuning the inductance of Josephson junction arrays without SQUIDs
Abstract
It is customary to use arrays of superconducting quantum interference devices (SQUIDs) for implementing magnetic fieldtunable inductors. Here, we demonstrate an equivalent tunability in a (SQUIDfree) array of single Al/AlOx/Al Josephson tunnel junctions. With the proper choice of junction geometry, a perpendicularly applied magnetic field bends along the plane of the superconductor and focuses into the tunnel barrier region due to a demagnetization effect. Consequently, the Josephson inductance can be efficiently modulated by the Fraunhoffertype supercurrent interference. The elimination of SQUIDs not only simplifies the device design and fabrication, but also facilitates a denser packing of junctions and, hence, a higher inductance per unit length. As an example, we demonstrate a transmission line, the wave impedance of which is fieldtuned in the range of $48~\textrm{k}\Omega$, centered around the important value of the resistance quantum $h/(2e)^2 \approx 6.5~\textrm{k}\Omega$.
 Publication:

arXiv eprints
 Pub Date:
 October 2022
 DOI:
 10.48550/arXiv.2210.12119
 arXiv:
 arXiv:2210.12119
 Bibcode:
 2022arXiv221012119K
 Keywords:

 Condensed Matter  Superconductivity;
 Condensed Matter  Mesoscale and Nanoscale Physics;
 Physics  Applied Physics;
 Quantum Physics