Reconfigurable Josephson Phase Shifter

Abstract

Phase shifter is one of the key elements of quantum electronics. In order to facilitate operation and avoid decoherence, it has to be reconfigurable, persistent, and nondissipative. In this work, we demonstrate prototypes of such devices in which a Josephson phase shift is generated by coreless superconducting vortices. The smallness of the vortex allows a broad-range tunability by nanoscale manipulation of vortices in a micron-size array of vortex traps. We show that a phase shift in a device containing just a few vortex traps can be reconfigured between a large number of quantized states in a broad [−3π, +3π] range.

Demonstration of a superconducting diode-with-memory, operational at zero magnetic field with switchable nonreciprocity

“…1 b represent the I c ( Φ ) modulation in a uniform junction with a trapped AV, placed symmetrically in the middle of the electrode, x v = L /2, at a distance z v = 0.1 L from the JJ (see the sketch in the inset). Stray fields from AV both distort and shift the I c ( H ) pattern 42 – 44 . This breaks the space-reversal, I c ± ( H ) ≠ I c ± ( − H ), but preserves the time-reversal, I c + ( H ) = ∣ I c − ( H )∣, symmetry.…”

“…As shown in refs. 43 , 44 , a flux offset introduced by AV in planar JJs is determined by the polar angle, Θ v , of the vortex within the junction (see the sketch in Fig. 1 b).…”

“…1 b). It depends on the vortex location ( x v , z v ), which is the tunning geometrical factor for the vortex-induced flux offset 43 , 44 . In Fig.…”

Superconducting Properties and Electron Scattering Mechanisms in a Nb Film with a Single Weak-Link Excavated by Focused Ion Beam

“…Structured thin films have shown promise for applications in different areas, including electronics and medicine. In particular, micro- and nanoscopic patterned superconducting films have received attention as their electric and magnetic properties may be optimized for technological purposes [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. In this context, focused ion beam (FIB) milling is an extraordinary tool that allows to obtain structures not possible to design by other nanofabrication methods [ 14 , 15 , 16 ].…”

“…In this context, focused ion beam (FIB) milling is an extraordinary tool that allows to obtain structures not possible to design by other nanofabrication methods [ 14 , 15 , 16 ]. FIB can reach spatial accuracy of about 20 nm and has been used to control the superconducting properties of several materials, including niobium films [ 4 , 6 , 8 , 10 , 13 , 17 , 18 , 19 , 20 ]. A serious drawback, however, is an inevitable contamination due to ion implantation that may cause severe damage to the milled material, modifying its physical characteristics [ 15 , 21 ] and being detrimental to superconducting specimens [ 22 , 23 ].…”