Nonreciprocal superconducting transport and the spin Hall effect in gyrotropic structures

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Kokkeler, Tim, Tokatly, Ilya, Bergeret, Sebastian
Format: Preprint
Published: 2023
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866911784424701952
author Kokkeler, Tim
Tokatly, Ilya
Bergeret, Sebastian
author_facet Kokkeler, Tim
Tokatly, Ilya
Bergeret, Sebastian
contents The search for superconducting systems exhibiting nonreciprocal transport and, specifically, the diode effect, has proliferated in recent years. This trend encompasses a wide variety of systems, including planar hybrid structures, asymmetric SQUIDs, and certain noncentrosymmetric superconductors. A common feature of such systems is a gyrotropic symmetry, realized on different scales and characterized by a polar vector. Alongside time-reversal symmetry breaking, the presence of a polar axis allows for magnetoelectric effects, which, when combined with proximity-induced superconductivity, results in spontaneous non-dissipative currents that underpin the superconducting diode effect. This symmetry established, we present a comprehensive theoretical study of transport in a lateral Josephson junctions composed of a normal metal supporting the spin Hall effect, and attached to a ferromagnetic insulator. Due to the presence of the latter, magnetoelectric effects arise without requiring external magnetic fields. We determine the dependence of the anomalous current on the spin relaxation length and the transport parameters commonly used in spintronics to characterize the interface between the metal and the ferromagnetic insulator. Therefore, our theory naturally unifies nonreciprocal transport in superconducting systems with classical spintronic effects, such as the spin Hall effect, spin galvanic effect, and spin Hall magnetoresistance. We propose an experiment involving measurements of magnetoresistance in the normal state and nonreciprocal transport in the superconducting state. Such experiment, on the one hand, allows for determining the parameters of the model and thus verifying with a greater precision the theories of magnetoelectric effects in normal systems. On the other hand, it contributes to a deeper understanding of the underlying microscopic origins that determine these parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2309_00495
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Nonreciprocal superconducting transport and the spin Hall effect in gyrotropic structures
Kokkeler, Tim
Tokatly, Ilya
Bergeret, Sebastian
Superconductivity
The search for superconducting systems exhibiting nonreciprocal transport and, specifically, the diode effect, has proliferated in recent years. This trend encompasses a wide variety of systems, including planar hybrid structures, asymmetric SQUIDs, and certain noncentrosymmetric superconductors. A common feature of such systems is a gyrotropic symmetry, realized on different scales and characterized by a polar vector. Alongside time-reversal symmetry breaking, the presence of a polar axis allows for magnetoelectric effects, which, when combined with proximity-induced superconductivity, results in spontaneous non-dissipative currents that underpin the superconducting diode effect. This symmetry established, we present a comprehensive theoretical study of transport in a lateral Josephson junctions composed of a normal metal supporting the spin Hall effect, and attached to a ferromagnetic insulator. Due to the presence of the latter, magnetoelectric effects arise without requiring external magnetic fields. We determine the dependence of the anomalous current on the spin relaxation length and the transport parameters commonly used in spintronics to characterize the interface between the metal and the ferromagnetic insulator. Therefore, our theory naturally unifies nonreciprocal transport in superconducting systems with classical spintronic effects, such as the spin Hall effect, spin galvanic effect, and spin Hall magnetoresistance. We propose an experiment involving measurements of magnetoresistance in the normal state and nonreciprocal transport in the superconducting state. Such experiment, on the one hand, allows for determining the parameters of the model and thus verifying with a greater precision the theories of magnetoelectric effects in normal systems. On the other hand, it contributes to a deeper understanding of the underlying microscopic origins that determine these parameters.
title Nonreciprocal superconducting transport and the spin Hall effect in gyrotropic structures
topic Superconductivity
url https://arxiv.org/abs/2309.00495