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

Informazioni relative al progetto

TopoInMulTermJJ

ID dell’accordo di sovvenzione: 753906

DOI

10.3030/753906

Progetto chiuso

Data della firma CE 27 Marzo 2017

Data di avvio 1 Ottobre 2017

Data di completamento 30 Settembre 2019

Finanziato da

• EXCELLENT SCIENCE - Marie Skłodowska-Curie Actions

Costo totale

€ 173 076,00

Contributo UE

€ 173 076,00

Coordinato da

UNIVERSITE GRENOBLE ALPES
France

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

Periodo di rendicontazione: 2017-10-01 al 2019-09-30

Sintesi del contesto e degli obiettivi generali del progetto

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.

Lavoro eseguito dall’inizio del progetto fino alla fine del periodo coperto dalla relazione e principali risultati finora ottenuti

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

Progressi oltre lo stato dell’arte e potenziale impatto previsto (incluso l’impatto socioeconomico e le implicazioni sociali più ampie del progetto fino ad ora)

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