Local Josephson vortex generation and manipulation with a Magnetic Force Microscope

Abstract

Josephson vortices play an essential role in superconducting quantum electronics devices. Often seen as purely conceptual topological objects, 2 π -phase singularities, their observation and manipulation are challenging. Here we show that in Superconductor—Normal metal—Superconductor lateral junctions Josephson vortices have a peculiar magnetic fingerprint that we reveal in Magnetic Force Microscopy (MFM) experiments. Based on this discovery, we demonstrate the possibility of the Josephson vortex generation and manipulation by the magnetic tip of a MFM, thus paving a way for the remote inspection and control of individual nano-components of superconducting quantum circuits.

Josephson junctions in a local inhomogeneous magnetic field

“…(12). This can cause a flux-flow phenomenon induced by the oscillating MFM tip, as recently reported [27]. Figure 5 shows a time sequence of solutions of Eq.…”

“…As discussed in Ref. [27], this provides a mechanism for detection of Josephson vortices by the MFM technique.…”

“…Two specific examples (without loosing generality) are considered with a local field induced either by an Abrikosov vortex, or by a tip of MFM. It is demonstrated that a time-dependent local field can induce a dynamic flux-flow phenomenon with either shuttling or unidirectional ratchet-like motion of Josephson vortices in the junction, which provides a mechanism for detection of Josephson vortices by MFM [27]. Analysis of the static case shows how the critical current versus magnetic field, I c (H), modulation patterns are distorted with introduction of the local inhomogeneous field.…”

Josephson current mediated by ballistic topological states in Bi2Te2.3Se0.7 single nanocrystals

“…j with Φ(H) = αHLW eff and Φ 0 = h/2e. The deviations are most probably due to a complex geometry of these junctions, flux focusing 61 , and a spatially inhomogeneous magnetic field.…”

Enabling autonomous scanning probe microscopy imaging of single molecules with deep learning

“…Since then, these techniques have not only been used to visualize a wide variety of samples from the µm-scale down to the single molecule and atom resolution, [3][4][5] they have also been used for sample manipulation and for performing a variety of spectroscopies providing information on e.g., chemical identity, mechanical, electrical, electrochemical and magnetic properties. [6][7][8][9] However, despite the possibilities that they offer, several bottlenecks are preventing broader use of SPMs. One of the major barriers to SPM use is the need for highly trained users to perform time-consuming experiments and to analyze and correctly interpret results that are often susceptible to artifacts.…”