Multi-Terminal Josephson Junctions as a novel platform for high dimensional topological matter

Projektinformationen

TopoInMulTermJJ

ID Finanzhilfevereinbarung: 753906

DOI

10.3030/753906

Projekt abgeschlossen

EK-Unterschriftsdatum 27 März 2017

Startdatum 1 Oktober 2017

Enddatum 30 September 2019

Finanziert unter

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Gesamtkosten

€ 173 076,00

EU-Beitrag

€ 173 076,00

Koordiniert durch

UNIVERSITE GRENOBLE ALPES
France

Periodic Reporting for period 1 - TopoInMulTermJJ (Multi-Terminal Josephson Junctions as a novel platform for high dimensional topological matter)

Berichtszeitraum: 2017-10-01 bis 2019-09-30

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

Josephson junctions host so-called Andreev bound states. As has been shown recently, the spectrum of Andreev bound states in an N-terminal Josephson junction as function of the superconducting phases can be viewed as a pseudo-bandstructure in N-1 dimension. This pseudo-bandstructure may have interesting topological properties. However, many questions concerning the characterization, classification, and manipulation of the topological states in multi-terminal Josephson junctions are still open. The objective of the project was to further explore this novel platform for topological matter.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

In the beginning of the project, general properties of multi-terminal Josephson junctions were investigated. Furthermore, it was shown that coupling two 3-terminal junctions via a common superconducting island makes it impossible to reach the Weyl points that may be present in the Andeev spectrum of a single junction. This rules out one of the original ideas in the proposal.

Subsequently, the effect of Berry curvature on electronic transport was studied. While the appearance of a first Chern number can be seen in the first order perturbation correction to the adiabatic result, here a second order perturbation expansion was performed to explore whether new phenomena appear. The results still have to be applied to a concrete realization that would allow one to interpret them

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

The researcher is planning to continue the investigation on the last project after the end of the fellowship. The identification of a measurable quantity probing the higher order terms is expected to stimulate further activity in the research field of topological properties of matter.

Examples of geometric setups of Multi-terminal Josephson junctions