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arXiv · 1905.12670

Gate Controlled Anomalous Phase Shift in Al/InAs Josephson Junctions

William Mayer·Matthieu C. Dartiailh·Joseph Yuan·Kaushini S. Wickramasinghe·Enrico Rossi·Javad Shabani
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Abstract

In a standard Josephson junction the current is zero when the phase difference between the superconducting leads is zero. This condition is protected by parity and time-reversal symmetries. However, the combined presence of spin-orbit coupling and magnetic field breaks these symmetries and can lead to a finite supercurrent even when the phase difference is zero. This is the so called anomalous Josephson effect -- the hallmark effect of superconducting spintronics --and can be characterized by the corresponding anomalous phase shift ($ϕ_0$). We report the observation of a tunable anomalous Josephson effect in InAs/Al Josephson junctions measured via a superconducting quantum interference device (SQUID). By gate controlling the density of InAs we are able to tune the spin-orbit coupling of the Josephson junction by more than one order of magnitude. This gives us the ability to tune $ϕ_0$, and opens several new opportunities for superconducting spintronics, and new possibilities for realizing and characterizing topological superconductivity.

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William Mayer, Matthieu C. Dartiailh, Joseph Yuan, Kaushini S. Wickramasinghe, Enrico Rossi, Javad Shabani. 2019-05-29. Gate Controlled Anomalous Phase Shift in Al/InAs Josephson Junctions. https://doi.org/10.1038/s41467-019-14094-1

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