Geometric dependence of critical current magnitude and nonreciprocity in planar Josephson junctions

Fuente: arXiv
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Autori principali: Schiela, William F., Mikalsen, Melissa, Strickland, William M., Shabani, Javad
Natura: Preprint
Pubblicazione: 2025
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author Schiela, William F.
Mikalsen, Melissa
Strickland, William M.
Shabani, Javad
author_facet Schiela, William F.
Mikalsen, Melissa
Strickland, William M.
Shabani, Javad
contents Planar Josephson junctions in a magnetic field exhibit the superconducting diode effect, by which the critical current magnitude depends on the polarity of the transport current. A number of different mechanisms for the effect have been proposed.Here, we study symmetric, T-shaped planar Josephson junctions with semiconducting weak links in an in-plane magnetic field perpendicular to an applied current bias. In particular, we vary the longitudinal width (i.e.\ parallel to the current) of the superconducting contacts and the voltage of an electrostatic gate. We observe an increase in both critical current and diode efficiency with increasing contact width and relate the critical current behavior to the induced coherence length of the Andreev bound states that mediate the supercurrent flow through the junction. We further observe a linear trend, with respect to inverse contact width, of the field at which the diode efficiency is maximized, which saturates as the contact width becomes large compared to the coherence length. The smaller field at which the critical current is maximized additionally exhibits a strong gate dependence. We interpret these observations in the context of multiple underlying mechanisms, including spin--orbit coupling and orbital effects.
format Preprint
id arxiv_https___arxiv_org_abs_2502_12400
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Geometric dependence of critical current magnitude and nonreciprocity in planar Josephson junctions
Schiela, William F.
Mikalsen, Melissa
Strickland, William M.
Shabani, Javad
Mesoscale and Nanoscale Physics
Materials Science
Planar Josephson junctions in a magnetic field exhibit the superconducting diode effect, by which the critical current magnitude depends on the polarity of the transport current. A number of different mechanisms for the effect have been proposed.Here, we study symmetric, T-shaped planar Josephson junctions with semiconducting weak links in an in-plane magnetic field perpendicular to an applied current bias. In particular, we vary the longitudinal width (i.e.\ parallel to the current) of the superconducting contacts and the voltage of an electrostatic gate. We observe an increase in both critical current and diode efficiency with increasing contact width and relate the critical current behavior to the induced coherence length of the Andreev bound states that mediate the supercurrent flow through the junction. We further observe a linear trend, with respect to inverse contact width, of the field at which the diode efficiency is maximized, which saturates as the contact width becomes large compared to the coherence length. The smaller field at which the critical current is maximized additionally exhibits a strong gate dependence. We interpret these observations in the context of multiple underlying mechanisms, including spin--orbit coupling and orbital effects.
title Geometric dependence of critical current magnitude and nonreciprocity in planar Josephson junctions
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2502.12400