Chiral topological superconductivity in Josephson junctions

AbstractPlanar Josephson junctions provide a versatile platform, alternative to the nanowire-based geometry, for the generation of the Majorana bound states, due to the additional phase tunability of the topological superconductivity. The proximity induction of chiral magnetism and superconductivity in a two-dimensional electron gas showed remarkable promise to manipulate topological superconductivity. Here, we consider a Josephson junction involving a skyrmion crystal and show that the chiral magnetism of the skyrmions can create and control the Majorana bound states without the requirement of an intrinsic Rashba spin-orbit coupling. Interestingly, the Majorana bound states in our geometry are realized robustly at zero phase difference at the junction. The skyrmion radius, being externally tunable by a magnetic field or a magnetic anisotropy, brings a unique control feature for the Majorana bound states.

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Missing Shapiro steps in topologically trivial Josephson junction on InAs quantum well

Nature Communications ◽

10.1038/s41467-020-20382-y ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Matthieu C. Dartiailh ◽

Joseph J. Cuozzo ◽

Bassel H. Elfeky ◽

William Mayer ◽

Joseph Yuan ◽

...

Keyword(s):

Quantum Wells ◽

Josephson Junctions ◽

Current Phase ◽

Majorana Fermions ◽

Spin Orbit Coupling ◽

Shapiro Steps ◽

Experimental Consequence ◽

Periodic Current ◽

Strong Spin ◽

Topological Superconductivity

AbstractJosephson junctions hosting Majorana fermions have been predicted to exhibit a 4π periodic current phase relation. One experimental consequence of this periodicity is the disappearance of odd steps in Shapiro steps experiments. Experimentally, missing odd Shapiro steps have been observed in a number of materials systems with strong spin-orbit coupling and have been interpreted in the context of topological superconductivity. Here we report on missing odd steps in topologically trivial Josephson junctions fabricated on InAs quantum wells. We ascribe our observations to the high transparency of our junctions allowing Landau-Zener transitions. The probability of these processes is shown to be independent of the drive frequency. We analyze our results using a bi-modal transparency distribution which demonstrates that only few modes carrying 4π periodic current are sufficient to describe the disappearance of odd steps. Our findings highlight the elaborate circumstances that have to be considered in the investigation of the 4π Josephson junctions in relationship to topological superconductivity.

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Crystalline anisotropic topological superconductivity in proximitized josephson junctions

Spintronics XIV ◽

10.1117/12.2595370 ◽

2021 ◽

Author(s):

Alex Matos-Abiague ◽

Joseph D. Pakizer ◽

Benedikt Scharf

Keyword(s):

Josephson Junctions ◽

Topological Superconductivity

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Topological superconductivity in planar Josephson junctions and dc-SQUIDs

Spintronics XIV ◽

10.1117/12.2595368 ◽

2021 ◽

Author(s):

Barış Pekerten ◽

Joseph D. Pakizer ◽

Benjamin S. Hawn ◽

Alex Matos-Abiague

Keyword(s):

Josephson Junctions ◽

Topological Superconductivity

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Skyrmion Control of Majorana States in Planar Josephson Junctions

10.21203/rs.3.rs-155447/v1 ◽

2021 ◽

Author(s):

Narayan Mohanta ◽

Satoshi Okamoto ◽

Elbio Dagotto

Keyword(s):

Josephson Junctions ◽

Bound States ◽

Spin Orbit Coupling ◽

Majorana Bound States ◽

Rashba Spin ◽

Dimensional Electron Gas ◽

And Control ◽

Zero Phase ◽

Additional Phase ◽

Topological Superconductivity

Abstract Planar Josephson junctions provide a versatile platform, alternative to the nanowire-based geometry, for the generation of the Majorana bound states, due to the additional phase tunability of the topological superconductivity. The proximity induction of chiral magnetism and superconductivity in a two-dimensional electron gas showed remarkable promises to manipulate topological superconductivity. Here, we consider a Josephson junction involving a skyrmion crystal and show that the chiral magnetism of the skyrmions can create and control the Majorana bound states without the requirement of an intrinsic Rashba spin-orbit coupling. Interestingly, the Majorana bound states in our geometry are realized robustly at zero phase difference at the junction. The skyrmion radius, being externally tunable by a magnetic field or a magnetic anisotropy, brings a unique control feature for the Majorana bound states.

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