Superconducting diodes from magnetization gradients

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The superconducting diode effect may exist in bulk systems as well as in junctions when time-reversal and inversion symmetries are simultaneously broken. Magnetization gradients and textures satisfy both requirements and therefore also allow for superconducting diodes. We concretely demonstrate such possibilities in two-dimensional superconductors. We first consider superconducting Rashba metals in the presence of an inhomogeneous out-of-plane exchange field. Using analytical arguments, we reveal that such magnetization gradients stabilize a helical superconducting ground state, similar to homogeneous in-plane magnetic fields. Our predictions are confirmed by employing self-consistent real-space numerical lattice simulations exemplified through the cases of a uniform magnetization gradient or a ferromagnetic domain wall. Furthermore, by considering a phase difference, we determine the nonreciprocal current-phase relations and explore their parameter dependence. Our calculations show that planar devices with out-of-plane magnetization gradients may be as efficient supercurrent rectifiers as their analogs induced by uniform in-plane fields. In addition, they feature the advantage that by means of tailoring the spatial profile of the out-of-plane magnetization, one may optimize and spatially control the diode effect. Finally, we show that superconducting diodes may become also accessible even in the absence of spin-orbit coupling by means of suitable spatially varying magnetization fields.
OriginalsprogEngelsk
Artikelnummer144503
TidsskriftPhysical Review B
Vol/bind109
Udgave nummer14
Antal sider13
ISSN2469-9950
DOI
StatusUdgivet - 2024

Bibliografisk note

Funding Information:
We acknowledge useful discussions with D. Agterberg, K. Flensberg, and M. Geier. M.R. acknowledges support from the Novo Nordisk Foundation Grant No. NNF20OC0060019.

Publisher Copyright:
© 2024 American Physical Society.

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