Direct Observation of a Superconducting Vortex Diode

Alon Gutfreund; Hisakazu Matsuki; Vadim Plastovets; Avia Noah; Laura Gorzawski; Nofar Fridman; Guang Yang; Alexander Buzdin; Oded Millo; Jason W. A. Robinson; Yonathan Anahory

doi:10.1038/s41467-023-37294-2

arXiv · 2301.07121

Direct Observation of a Superconducting Vortex Diode

Alon Gutfreund·Hisakazu Matsuki·Vadim Plastovets·Avia Noah·Laura Gorzawski·Nofar Fridman·Guang Yang·Alexander Buzdin·Oded Millo·Jason W. A. Robinson·Yonathan Anahory

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Abstract

The interplay between magnetism and superconductivity can lead to unconventional proximity and Josephson effects. A related phenomenon that has recently attracted considerable attention is the superconducting diode effect, in which a non-reciprocal critical current emerges. Although superconducting diodes based on superconducting/ferromagnetic (S/F) bilayers were demonstrated more than a decade ago, the precise underlying mechanism remains unclear. While not formally linked to this effect, the Fulde-Ferrell-Larkin-Ovchinikov (FFLO) state is a plausible mechanism, due to the 2-fold rotational symmetry breaking caused by the finite center-of-mass-momentum of the Cooper pairs. Here, we directly observe, for the first time, a tunable superconducting vortex diode in Nb/EuS (S/F) bilayers. Based on our nanoscale SQUID-on-tip (SOT) microscope and supported by in-situ transport measurements, we propose a theoretical model that captures our key results. Thus, we determine the origin for the vortex diode effect, which builds a foundation for new device concepts.

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cond-mat.supr-con cond-mat.mes-hall cond-mat.mtrl-sci

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Alon Gutfreund, Hisakazu Matsuki, Vadim Plastovets, Avia Noah, Laura Gorzawski, Nofar Fridman, Guang Yang, Alexander Buzdin, Oded Millo, Jason W. A. Robinson, Yonathan Anahory. 2023-01-17. Direct Observation of a Superconducting Vortex Diode. https://doi.org/10.1038/s41467-023-37294-2

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